A Guide to the Study of Fishes, Volume 1 (of 2)

CHAPTER XXI
CLASSIFICATION OF FISHES

Taxonomy.—Classification, as Dr. Elliott Coues has well said,[147] is a natural function of "the mind which always strives to make orderly disposition of its knowledge and so to discover the reciprocal relations and interdependencies of the things it knows. Classification presupposes that there do exist such relations, according to which we may arrange objects in the manner which facilitates their comprehension, by bringing together what is like and separating what is unlike, and that such relations are the result of fixed inevitable law. It is therefore taxonomy (τάξις, away; νόμος, law) or the rational, lawful disposition of observed facts."

A perfect taxonomy is one which would perfectly express all the facts in the evolution and development of the various forms. It would recognize all the evidence from the three ancestral documents, palæontology, morphology, and ontogeny. It would consider structure and form independently of adaptive or physiological or environmental modifications. It would regard as most important those characters which had existed longest unchanged in the history of the species or type. It would regard as of first rank those characters which appear first in the history of the embryo. It would regard as of minor importance those which had arisen recently in response to natural selection or the forced alteration through pressure of environment, while fundamental alterations as they appear one after another in geologic time would make the basal characters of corresponding groups in taxonomy. In a perfect taxonomy or natural system of classification animals would not be divided into groups nor ranged in linear series. We should imagine series variously and divergently branched, with each group at its earlier or lower end passing insensibly into the main or primitive stock. A very little alteration now and then in some structure is epoch-making, and paves the way through specialization to a new class or order. But each class or order through its lowest types is interlocked with some earlier and otherwise diverging group.

Defects in Taxonomy.—A sound system of taxonomy of fishes should be an exact record of the history of their evolution. But in the limitations of book-making, this transcript must be made on a flat page, in linear series, while for centuries and perhaps forever whole chapters must be left vacant and others dotted everywhere with marks of doubt. For science demands that positive assertion should not go where certainty cannot follow. A perfect taxonomy of fishes would be only possible through the study, by some Artedi, Müller, Cuvier, Agassiz, Traquair, Gill, or Woodward, of all the structures of all the fishes which have ever lived. There are many fishes living in the sea which are not yet known to any naturalist, many others are known from one or two specimens, but not yet accessible to students in other continents. Many are known externally from specimens in bottles or drawings in books, but have not been studied thoroughly by any one, and the vast multitude of species have perished in Palæozoic, Mesozoic, and Tertiary seas without leaving a tooth or bone or fin behind them. With all this goes human fallibility, the marring of our records, such as they are, by carelessness, prejudice, dependence, and error. Chief among these defects are the constant mistaking of analogy for homology, and the inability of men to trust their own eyes as against the opinion of the greater men who have had to form their opinions before all evidence was in. Because of these defects, the current system of classification is always changing with each accession of knowledge.

The result is, again to quote from Dr. Coues, "that the natural classification, like the elixir of life or the philosopher's stone, is a goal far distant."

Analogy and Homology.—Analogy, says Dr. Coues, "is the apparent resemblance between things really unlike—as the wing of a bird and the wing of a butterfly, as the lungs of a bird and the gills of a fish. Homology is the real resemblance, or true relation between things, however different they may appear to be—as the wing of a bird and the foreleg of a horse, the lungs of a bird and the swim-bladder of a fish. The former commonly rests upon mere functional, i.e. physiological, modifications; the latter is grounded upon structural, i.e., morphological, identity or unity. Analogy is the correlative of physiology, homology of morphology; but the two may be coincident, as when structures identical in morphology are used for the same purposes, and are therefore physiologically identical. Physiological diversity of structure is incessant, and continually interferes with morphological identity of structure, to obscure or obliterate the indications of affinity the latter would otherwise express clearly.... We must be on our guard against those physiological appearances which are proverbially deceptive!"

"It is possible and conceivable that every animal should have been constructed upon a plan of its own, having no resemblance whatever to the plan of any other animal. For any reason we can discover to the contrary, that combination of natural forces which we term life might have resulted from, or been manifested by, a series of infinitely diverse structures; nor would anything in the nature of the case lead us to suspect a community of organization between animals so different in habit and in appearance as a porpoise and a gazelle, an eagle and a crocodile, or a butterfly and a lobster. Had animals been thus independently organized, each working out its life by a mechanism peculiar to itself, such a classification as that now under contemplation would be obviously impossible; a morphological or structural classification plainly implying morphological or structural resemblances in the things classified.

"As a matter of fact, however, no such mutual independence of animal forms exists in nature. On the contrary, the members of the animal kingdom, from the highest to the lowest, are marvelously connected. Every animal has something in common with all its fellows—much with many of them, more with a few, and usually so much with several that it differs but little from them.

"Now, a morphological classification is a statement of these gradations of likeness which are observable in animal structures, and its objects and uses are manifold. In the first place, it strives to throw our knowledge of the facts which underlie, and are the cause of, the similarities discerned into the fewest possible general propositions, subordinated to one another, according to their greater or less degree of generality; and in this way it answers the purpose of a memoria technica, without which the mind would be incompetent to grasp and retain the multifarious details of anatomical science."

Coues on Classification.—It is obvious that fishes like other animals may be classified in numberless ways, and as a matter of fact by numberless men they have been classified in all sorts of fashions. "Systems," again quoting from Dr. Coues, "have been based on this and that set of characters and erected from this or that preconception in the mind of the systematist.... The mental point of view was that every species of bird (or of fish) was a separate creature, and as much of a fixture in nature's museum as any specimen in a naturalist's cabinet. Crops of classifications have been sown in the fruitful soil of such blind error, but no lasting harvest has been reaped.... The genius of modern taxonomy seems to be so certainly right, to be tending so surely even if slowly in the direction of the desired consummation, that all differences of opinion we hope will soon be settled, and defect of knowledge, not perversity of mind, is the only obstacle in the way of success. The taxonomic goal is not now to find the way in which birds (or other animals) may be most conveniently arranged, but to discover their pedigree, and so construct their family tree. Such a genealogical table, or phylum (φῦλον, tribe, race, stock), as it is called, is rightly considered the only taxonomy worthy the name—the only true or natural classification. In attempting this end, we proceed upon the belief that, as explained above, all birds, like all other animals and plants, are related to each other genetically, as offspring are to parents, and that to discover their generic relations is to bring out their true affinities—in other words, to reconstruct the actual taxonomy of nature. In this view there can be but one 'natural' classification, to the perfecting of which all increase in our knowledge of the structure of birds infallibly and inevitably tends. The classification now in use or coming into use is the result of our best endeavors to accomplish this purpose, and represents what approach we have made to this end. It is one of the great corollaries of that theorem of evolution which most naturalists are satisfied has been demonstrated. It is necessarily a morphological classification; that is, one based solely upon considerations of structure or form (μορφή, form, morphe), and for the following reasons: Every offspring tends to take on precisely the form or structure of its parents, as its natural physical heritage; and the principle involved, or the law of heredity, would, if nothing interfered, keep the descendants perfectly true to the physical characters of their progenitors; they would 'breed true' and be exactly alike. But counter influences are incessantly operative, in consequence of constantly varying external conditions of environment; the plasticity of organization of all creatures rendering them more or less susceptible of modifications by such means, they become unlike their ancestors in various ways and to different degrees. On a large scale is thus accomplished, by natural selection and other natural agencies, just what man does in a small way in producing and maintaining different breeds of domestic animals. Obviously, amidst such ceaselessly shifting scenes, degrees of likeness or unlikeness of physical structure indicate with the greatest exactitude the nearness or remoteness of organisms in kinship. Morphological characters derived from the examination of structure are therefore the surest guides we can have to the blood relationships we desire to establish; and such relationships are the 'natural affinities' which all classification aims to discover and formulate."

Species as Twigs of a Genealogical Tree.—In another essay Dr. Coues has compared species of animals to "the twigs of a tree separated from the parent stem. We name and arrange them arbitrarily in default of a means of reconstructing the whole tree according to nature's ramifications." If one had a tree, all in fragments, pieces of twig and stem, some of them lost, some destroyed, and some not yet separated from the mass not yet picked over, and wished to place each part where he could find it, he would be forced to adopt some system of natural classification. In such a scheme he would lay those parts together which grew from the same branch. If he were compelled to arrange all the fragments in a linear series, he would place together those of one branch, and when these were finished he would begin with another. If all this were a matter of great importance and extending over years or over many lifetimes, with many errors to be made and corrected, a set of names would be adopted—for the main trunk, for the chief branches, the lesser branches, and on down to the twigs and buds.

A task of this sort on a world-wide scale is the problem of systematic zoology. There is reason to believe that all animals and plants sprang from a single stock. There is reasonable certainty that all vertebrate animals are derived from a single origin. These vertebrate animals stand related to each other, like the twigs of a gigantic tree of which the lowermost branches are the aquatic forms to which we give the name of fishes. The fishes are here regarded as composed of six classes or larger lines of descent. Each of these, again, is composed of minor divisions called orders. The different species or ultimate kinds of animals are grouped in genera. A genus is an assemblage of closely related species grouped around a central species as type. The type of a genus is, in common usage, that species with which the name of the genus was first associated. The name of the genus as a noun, often with that of the species which is an adjective in signification if not in form, constitutes the scientific name of the species. Thus Petromyzon is the genus of the common large lamprey, marinus is its species, and the scientific name of the species is Petromyzon marinus. Petromyzon means stone-sucker; marinus, of the sea, thus distinguishing it from a species called fluviatilis, of the river. In like fashion all animals and plants are named in scientific record or taxonomy. Technical names are necessary because vernacular names fail. Half a million kinds of animals are known, while not half a thousand vernacular names exist in any language. And these are always loosely used, half a dozen of them often for the same species, one name often for a dozen species.

In the same way, whenever we undertake an exact description, we must use names especially devised for that purpose. We cannot use the same names for the bones of the head of a fish and those of the head of a man, for a fish has a different series of bones, and this series is different with different fishes.

Nomenclature.—A family in zoology is an assemblage of related genera. The name of a family, for convenience, always ends in the patronymic idæ, and it is always derived from the leading genus, that is, the one best known or earliest studied. Thus all lampreys constitute the family Petromyzonidæ. An order may contain one or more families. An order is a division of a larger group; a family an assemblage of related smaller groups. Intermediate groups are often recognized by the prefixes sub or super. A subgenus is a division of a genus. A subspecies is a geographic race or variation within a species; a super-family a group of allied families. Binomial nomenclature, or the use of the name of genus and species as a scientific name, was introduced into science as a systematic method by Linnæus. In the tenth edition of his Systema Naturæ, published in 1758, this method was first consistently applied to animals. By common consent the scientific naming of animals begins with this year, and no account is taken of names given earlier, as these are, except by accident, never binomial. Those authors who wrote before the adoption of the rule of binomials and those who neglected it are alike "ruled out of court." The idea of genus and species was well understood before Linnæus, but the specific name used was not one word but a descriptive phrase, and this phrase was changed at the whim of the different authors.

Nomenclature of Trunkfishes.—Examples of such names are those of the West Indian trunkfish, or cuckold (Ostracion tricorne, Linnæus). Lister refers to a specimen in 1686 as "Piscis triangularis capiti cornutu cui e media cauda cutanea aculeus longus erigitus." This Artedi alters in 1738 to Ostracion triangulatus aculeis duobus in capite et unico longiore superne ad caudam. This is more accurately descriptive and it recognizes the existence of a generic type, Ostracion, or trunkfish, to cover all similar fishes. French writers transformed this into various phrases beginning "Coffre triangulaire à trois cornes," or some similar descriptive epithet, and in English or German it was likely to wander still farther from the original. But Linnæus condenses it all in the word tricornis, which, although not fully descriptive, is still a name which all future observers can use and recognize.

It is true that common consent fixes the date of the beginning of nomenclature at 1758. But to this there are many exceptions. Some writers date genera from the first recognition of a collective idea under a single name. Others follow even species back through the occasional accidental binomials. Most British writers have chosen the final and completed edition of the Systema Naturæ, the last work of Linnæus, in 1766, in preference to the earlier volume. But all things considered, justice and convenience alike seem best served by the use of the edition of 1758.

Synonymy and Priority.—Synonymy is the record of the names applied at different times to the same group or species. With characteristic pungency Dr. Coues defines synonymy as "a burden and a disgrace to science." It has been found that the only way to prevent utter confusion is to use for each genus or species the first name applied to it and no other. The first name, once properly given, is sacred because it is the right name. All other later names whatever their appropriateness are wrong names. In science, of necessity, a name is a name without any necessary signification. For this reason and for the further avoidance of confusion, it remains as it was originally spelled by the author, obvious misprints aside, regardless of all possible errors in classical form or meaning. The names in use are properly written in Latin or in Latinized Greek, the Greek forms being usually preferred as generic names, the Latin adjectives for names of species. Many species are named in honor of individuals, these names being usually given the termination of the Latin genitive, as Sebastodes gillii, Liparis agassizi. In recent custom all specific names are written with the small initial; all generic names with the capital.

One class of exceptions must be made to the law of priority. No generic name can be used twice among animals, and no specific name twice in the same genus. Thus the name Diabasis has to be set aside in favor of the next name Hæmulon, because Diabasis was earlier used for a genus of beetles. The specific name Pristipoma humile is abandoned, because there was already a humile in the genus Pristipoma.

The Conception of Genus.—In the system of Linnæus, a genus corresponds roughly to the modern conception of a family. Most of the primitive genera contained a great variety of forms, as well as usually some species belonging to other groups disassociated from their real relationships.

As greater numbers of species have become known the earlier genera have undergone subdivision until in the modern systems almost any structural character not subject to intergradation and capable of exact definition is held to distinguish a genus. As the views of these characters are undergoing constant change, and as different writers look upon them from different points of view, or with different ideas of convenience, we have constant changes in the boundaries of genera. This brings constant changes in the scientific names, although the same specific name should be used whatever the generic name to which it may be attached. We may illustrate these changes and the burden of synonymy as well by a concrete example.

The Trunkfishes.—The horned trunkfish, or cuckold, of the West Indies was first recorded by Lister in 1686, in the descriptive phrase above quoted. Artedi, in 1738, recognized that it belonged with other trunkfishes in a group he called Ostracion. This, to be strictly classic, he should have written Ostracium, but he preferred a partly Greek form to the Latin one. In the Nagg's Head Inn in London, Artedi saw a trunkfish he thought different, having two spines under the tail, while Lister's figure seemed to show one spine above. This Nagg's Head specimen Artedi called "Ostracion triangulatus duobus aculeis in fronte et totidem in imo ventre subcaudalesque binis."

Next came Linnæus, 1758, who named Lister's figure and the species it represented, Ostracion tricornis, which should in strictness have been Ostracion tricorne, as ὀστρακίον, a little box, is a neuter diminutive. The Nagg's Head fish he named Ostracion quadricornis. The right name now is Ostracion tricornis, because the name tricornis stands first on the page in Linnæus' work, but Ostracion quadricornis has been more often used by subsequent authors because it is more truthful as a descriptive phrase. In 1798, Lacépède changed the name of Lister's fish to Ostracion listeri, a needless alteration which could only make confusion.

In 1818, Dr. Samuel Latham Mitchill, receiving a specimen from below New Orleans, thought it different from tricornis and quadricornis and called it Ostracion sexcornutus; Dr. Holard, of Paris, in 1857, named a specimen Ostracion maculatus, and at about the same time Bleeker named two others from Africa which seem to be the same thing, Ostracion guineensis and Ostracion gronovii. Lastly, Poey calls a specimen from Cuba Acanthostracion polygonius, thinking it different from all the rest, which it may be, although my own judgment is otherwise. This brings up the question of the generic name. Among trunkfishes there are four-angled and three-angled kinds, and of each form there are species with and without horns and spines. The original Ostracion of Linnæus we may interpret as being Ostracion cubicus of the coasts of Asia, a species similar to the Ostracion rhinorhynchus. This species, cubicus, we call the type species of the genus, as the Nagg's Head specimen of Artedi was the type specimen of the species quadricornus, and the one that was used for Lister's figure the type specimen of tricornis.

Ostracion cubicus is a four-angled species, and when the trunkfishes were regarded as a family (Ostraciidæ), the three-angled ones were set off as a separate genus. For this two names were offered, both by Swainson in 1839. For trigonus, a species without horns before the eyes, he gave the name Lactophrys, and for triqueter, a species without spines anywhere, the name of Rhinesomus. Most recent American authors have placed the three-cornered species which are mostly American in one genus, which must therefore be called Lactophrys. Of this name Rhinesomus is a synonym, and our species should stand as Lactophrys tricornis. The fact that Lactophrys as a word (from Latin lætus, smooth; Greek ὀφρύς, eyebrow; or else from lactoria, a milk cow, and ὀφρύς) is either meaningless or incorrectly written makes no difference with the necessity for its use.

In 1862, Bleeker undertook to divide these fishes differently. Placing all the hornless species, whether three-angled or four-angled, in Ostracion, he proposed the name Acanthostracion for the species with horns, tricornis being the type. But Acanthostracion has not been usually adopted except as the name of a section under Lactophrys. The three-angled American species are usually set apart from the four-angled species of Asia, and our cuckold is called Lactophrys tricornis. But it may be with perfect correctness called Ostracion tricorne, in the spirit called conservative. Or with the "radical" systematists we may accept the finer definition and again correctly call it Acanthostracion tricorne. But to call it quadricornis or listeri or maculatus with any generic name whatever would be to violate the law of priority.

Trinomial Nomenclature.—By trinomial nomenclature we mean the use of a second subordinate specific name to designate a geographic subspecies, variety, or other intergrading race. Thus Salmo clarki virginalis indicates the variety of Clark's trout, or the cut-throat trout, found in the lakes and streams of the Great Basin of Utah, as distinguished from the genuine Salmo clarkii of the Columbia. Trinomials are not much used among fishes, as we are not yet able to give many of the local forms correct and adequate definition such as is awarded to similar variations among birds and mammals. Usually varieties in ichthyology count as species or as nothing.

Meaning of Species.—Quoting once more from the admirable essay of Dr. Coues on the taxonomy of birds: "The student cannot be too well assured that no such things as species, in the old sense of the word, exist in nature any more than have genera or families an actual existence. Indeed they cannot be, if there is any truth in the principles discussed in our earlier paragraphs. Species are simply ulterior modifications, which once were, if they be not still, inseparably linked together; and their nominal recognition is a pure convention, like that of a genus. More practically hinges upon the way we regard them than turns upon our establishment of higher groups, simply because upon the way we decide in this case depends the scientific labeling of specimens. If we are speaking of a robin, we do not ordinarily concern ourselves with the family or order it belongs to, but we do require a technical name for constant use. That name is compounded of its genus, species, and variety. No infallible rule can be laid down for determining what shall be held to be a species, what a conspecies, subspecies, or variety. It is a matter of tact and experience, like the appreciation of the value of any other group in zoology. There is, however, a convention upon the subject, which the present workers in ornithology in this country find available; at any rate we have no better rule to go by. We treat as "specific" any form, however little different from the next, that we do not know or believe to intergrade with that next one, between which and the next one no intermediate equivocal specimens are forthcoming, and none, consequently, are supposed to exist. This is to imply that differentiation is accomplished, the links are lost and the characters actually become "specific." We treat as "varietal" of each other any forms, however different in their extreme manifestation, which we know to intergrade, having the intermediate specimens before us, or which we believe with any good reason do intergrade. If the links still exist, the differentiation is still incomplete, and the characters are not specific, but only varietal, in the literal sense of these terms."

Generalization and Specialization.—A few terms in common use may receive a moment's discussion. A type or group is said to be specialized when it has a relatively large number of peculiarities or when some one peculiarity is carried to an extreme. A sculpin is a specialized fish having many unusual phases of development, as is also a swordfish, which has a highly peculiar structure in the snout. A generalized type is one with fewer peculiarities, as the herring in comparison with the sculpin. In the process of evolution generalized types usually give place to specialized ones. Generalized types are therefore as a rule archaic types. The terms high and low are also relative, a high type being one with varied structure and functions. Low types may be primitively generalized, as the lancelet in comparison with all other fishes, or the herring in comparison with the perch, or they may be due to degradation, a loss of structures which have been elaborately specialized in their ancestry. The sea-snail (Liparis), an ally of the sculpin, with scales lost and fins deteriorated is an example of a low type which is specialized as well as degraded.

High and Low Forms.—In the earlier history of ichthyology much confusion resulted from the misconception of the terms "high" and "low." Because sharks appeared earlier than bony fishes, it was assumed that they should be lower than any of their subsequent descendants. That the brain and muscular system in sharks was more highly developed than in most bony fishes seemed also certain. Therefore it was thought that the teleost series could not have had a common origin with the series of sharks. It is now understood that evolution means chiefly adaptation. The teleost is adapted to its mode of life, and to that end it is specialized in fin and skeleton rather than in brain and nerves. All degeneration is associated with specialization. The degeneration of the blindfish is a specialization for better adaptation to life in the darkness of caves; the degeneration of the deep-sea fish meets the demands of the depths, the degeneration of the globefish means the sinking of one line of functions in the extension of some other.

Referring to his own work on the fossil fishes in the early forties, Professor Agassiz once said to the writer: "At that time I was on the verge of anticipating the views of Darwin, but it seemed to me that the facts were contrary to the theories of evolution. We had the highest fishes first." This statement leads us to consider what is meant by high and low. Undoubtedly the sharks are higher than the bony fishes in the sense of being nearer to the higher vertebrates. In brain, muscle, teeth, and reproductive structures they are also more highly developed. In all skeletal and cranial characters the sharks stand distinctly lower. But the essential fact, so far as evolution is concerned, is not that the sharks are high or low. They are, in almost all respects, distinctly generalized and primitive. The bony fishes are specialized in various ways through adaptation to the various modes of life they lead. Much of this specialization involves corresponding degeneration of organs whose functions have ceased to be important. As a broad proposition it is not true that "we had our highest fishes first," for in a complete definition of high and low, the specialized perch or bass stands higher. But whether true or not, it does not touch the question of evolution which is throughout a process of adaptation to conditions of life.

Referring to the position of Agassiz and his early friend and disciple, Hugh Miller, Dr. Traquair (1900) uses these words in an address at Bradford, England:

"It cannot but be acknowledged that the paleontology of fishes is not less emphatic in the support of descent than that of any other division of the animal kingdom. But in former days the evidence of fossil ichthyology was by some read otherwise.

"It is now a little over forty years since Hugh Miller died: he who was one of the first collectors of the fossil fishes of the Scottish old red sandstone, and who knew these in some respects better than any other man of his time, not excepting Agassiz himself. Yet his life was spent in a fierce denunciation of the doctrine of evolution, then only in its Lamarckian form, as Darwin had not yet electrified the world with his 'Origin of Species.' Many a time I wonder greatly what Hugh Miller would have thought had he lived a few years longer, so as to have been able to see the remarkable revolution which was wrought by the publication of that book.

"The main argument on which Miller rested was the 'high' state of organization of the ancient fishes of the Paleozoic formations, and this was apparently combined with a confident assumption of the completeness of the geological record. As to the first idea, we know of course that evolution means the passage from the more general to the more special, and that as the general result an onward advance has taken place; yet 'specialization' does not always or necessarily mean 'highness' of organization in the sense in which the term is usually employed. As to the idea of the perfection of the geological record, that of course is absurd.

"We do not and cannot know the oldest fishes, as they would not have had hard parts for preservation, but we may hope to come to know many more old ones, and older ones still than we do at present. My experience on the subject of fossil ichthyology is that it is not likely to become exhausted in our day.

"We are introduced at a period far back in geological history to certain groups of fishes, some of which certainly are high in organization as animals, but yet of generalized type, being fishes and yet having the potentiality of higher forms. But because their ancestors are unknown to us, that it is no evidence that they did not exist, and cannot overthrow the morphological testimony in favor of evolution with which the record actually does furnish us. We may therefore feel very sure that fishes or 'fish-like vertebrates' lived long ages before the oldest forms with which we are acquainted came into existence.

"The modern type of bony fishes, though not so 'high' in many anatomical points as that of the Selachii, Crossopterygii, Dipnoi, Acipenseroidei, and Lepidosteoidei of the Palæozoic and Mesozoic eras, is more specialized in the direction of the fish proper, and, as already indicated, specialization and 'highness' in the ordinary sense of the word are not necessarily coincident. But ideas about these things have undergone a wonderful change since those pre-Darwinian days, and though we shall never be able fully to unravel the problems concerning the descent of animals, we see many things a great deal more clearly now than we did then."

Dr. Gill observes: "Perhaps there are no words in science that have been productive of more mischief and more retarded the progress of biological taxonomy than those words pregnant with confusion, High and Low, and it were to be wished that they might be erased from scientific terminology. They deceive the person to whom they are addressed. They insensibly mislead the one who uses them. Psychological prejudices and fancies are so inextricably associated with these words that the use of them is provocative of such ideas. The words, generalized and specialized, having become almost limited to the expression of the ideas which the scientific biologist wishes to unfold by the others, can with great gain be employed in their stead." ("Families of Fishes," 1872.)

The Problem of the Highest Fishes.—As to which fishes should be ranked highest and which lowest, Dr. Gill gives ("Families of Fishes," 1872) the following useful discussion: "While among the mammals there is almost universal concurrence as to the forms entitled to the first as well as the last places, naturalists differ much as to the 'highest' of the ichthyoid vertebrates, but are all of one accord respecting the form to be designated as the 'lowest.' With that admitted lowest form as a starting-point, inquiry may be made respecting the forms which are successively most nearly related.

"No dissent has ever been expressed from the proposition that the Leptocardians (Branchiostoma) are the lowest of the vertebrates; while they have doubtless deviated much from the representatives of the immediate line of descent of the higher vertebrates, and are probably specialized considerably, in some respects, in comparison with those vertebrates from which they (in common with the higher forms) have descended, they undoubtedly have diverged far less, and furnish a better hint as to the protovertebrates than any other form.

"Equally undisputed it is that most nearly related to the Leptocardians are the Marsipobranchiates (Lampreys, etc.), and the tendency has been rather to overlook the fundamental differences between the two, and to approximate them too closely, than the reverse.

"But here unanimity ends, and much difference of opinion has prevailed with respect to the succession in the system of the several subclasses (by whatever name called) of true fishes: (1) Some (e.g., Cuvier, J. Müller, Owen, Lütken, Cope) arranging next to the lowest the Elasmobranchiates, and, as successive forms, the Ganoids and Teleosteans; (2) while others (e.g., Agassiz, Dana, Duméril, Günther) adopt the sequence Leptocardians, Marsipobranchiates, Teleosteans, Ganoids, and Elasmobranchiates. The source of this difference of opinion is evident and results partly from metaphysical or psychological considerations, and partly from those based (in the case of the Ganoids) on real similarities and affinities.

"The evidence in favor of the title of the Elasmobranchiates to the 'highest' rank is based upon (1) the superior development of the brain; (2) the development of the egg, and the ovulation; (3) the possession of a placenta; and (4) the complexity of the organs of generation.

"(1) It has not been definitely stated wherein the superior development of the brain consists, and as it is not evident to the author, the vague claim can only be met by this simple statement; it may be added, however, that the brains comparable in essentials and most similar as a whole to those of the Marsipobranchiates are those of the sharks. In answer to the statement that the sharks exhibit superior intelligence, and thus confirm the indications of cerebral structure, it may be replied that the impression is a subjective one, and the author has not been thus influenced by his own observations of their habits. Psychological manifestations, at any rate, furnish too vague criteria to be available in exact taxonomy.

"(2) If the development of the eggs, their small number, and their investment in cases are arguments in favor of the high rank of the Elasmobranchiates, they are also for the Marsipobranchiates, and thus prove too much or too little for the advocates of the views discussed. The variation in number of progeny among true fishes (e.g., Cyprinodonts, Embiotocids) also demonstrates the unreliability of those modifications per se.

"(3) The so-called placenta of some Elasmobranchiates may be analogous to that of mammals, but that it is not homologous (i.e., homogenetic) is demonstrable from the fact that all the forms intervening between them and the specialized placental mammals are devoid of a placenta, and by the variation (presence or want) among the Elasmobranchiates themselves.

"(4) The organs of generation in the Elasmobranchiates are certainly more complex than in most other fishes, but as the complexity results from specialization of parts sui generis and different from those of the higher (quadruped) vertebrates, it is not evident what bearing the argument has. If it is claimed simply on the ground of specialization, irrespective of homological agreement with admitted higher forms, then are we equally entitled to claim any specialization of parts as evidence of high rank, or at least we have not been told within what limits we should be confined. The Cetaceans, for example, are excessively specialized mammals, and, on similar grounds, would rank above the other mammals and man; the aye-aye exhibits in its dentition excessive specialization and deviation from the primitive type (as exhibited in its own milk teeth) of the Primates, and should thus also rank above man. It is true that in other respects the higher primates (even including man) may be more specialized, but the specialization is not as obvious as in the cases referred to, and it is not evident how we are to balance irrelative specializations against each other, or even how we shall subordinate such cases. We are thus compelled by the reductio ad absurdum to the confession that irrelative specialization of single organs is untrustworthy, and are fain to return to that better method of testing affinities by the equation of agreement in whole and after the elimination of special teleological modifications.

"The question then recurs, What forms are the most nearly allied to the Marsipobranchiates, and what show the closest approach in characteristic features? And in response thereto the evidence is not undecisive. Wide as is the gap between Marsipobranchiates and fishes, and comparatively limited as is the range of the latter among themselves, the Elasmobranchiates are very appreciably more like, and share more characters in common with them, than any other; so much is this the case that some eminent naturalists (e.g., Pallas, Geoffroy, St. Hilaire, Latreille, Agassiz, formerly Lütken) have combined the two forms in a peculiar group, contradistinguished from the other fishes. The most earnest and extended argument in English, in favor of this combination has been published by Professor Agassiz in his 'Lake Superior,' but that eminent naturalist subsequently arrived at the opposite conclusions already indicated.

"The evidences of the closer affinity of the Elasmobranchiates (than of any other fishes) with the Marsipobranchiates are furnished by (1) the cartilaginous condition of the skeleton; (2) the post-cephalic position of the branchiæ; (3) the development of the branchiæ and their restriction to special chambers; (4) the larger number of the branchiæ; (5) the imperfect development of the skull; (6) the mode of attachment of the teeth; (7) the slight degree of specialization of the rays of the fins; and (8) the rudimentary condition of the shoulder-girdle."

CHAPTER XXII
THE HISTORY OF ICHTHYOLOGY

Science consists of human experience, tested and placed in order. The science of ichthyology represents our knowledge of fishes, derived from varied experiences of man, tested by methods or instruments of precision and arranged in orderly sequence. This science, in common with every other, is the work of many persons, each in his own field, and each contributing a series of facts, a series of tests of the alleged facts of others, or some improvement in the method of arrangement. As in other branches of science, this work has been done by sincere, devoted men, impelled by a love for this kind of labor, and having in view, as "the only reward they asked, a grateful remembrance of their work." And in token of this reward it is well sometimes, in grateful spirit, to go over the names of those who made even its present stage of completeness possible.

We may begin the history of ichthyology with that of so many others of the sciences, with the work of Aristotle (383-322 B.C.). This wonderful observer recorded many facts concerning the structure and habits of the fishes of Greece, and in almost every case his actual observation bears the closest modern test. These observations were hardly "set in order." The number of species he knew was small, about 118 in all, and it did not occur to him that they needed classification. His ideas of species were those of the fishermen, and the local vernacular supplied him with the only names needed in his records.

As Dr. Günther wisely observes, "It is less surprising that Aristotle should have found so many truths as that none of his followers should have added to them." For nearly 1800 years the scholars of the times copied the words of Aristotle, confusing them by the addition of fabulous stories and foolish superstitions, never going back to nature herself, "who leads us to absolute truth whenever we wander." A few observations were made by Caius Plinius, Claudius Ælianus, Athenæus and others. Theophrastus (370-270 B.C.) wrote on the fishes which may live out of water. About 400 A.D., Decius Magnus Ausonius wrote a pleasing little poem on the Moselle, setting forth the merits of its various fishes. It was not, however, until the middle of the seventeenth century that any advance was made in the knowledge of fishes. At that time the development of scholarship among the nations of Europe was such that a few wise men were able to grasp the idea of species.

In 1553, Pierre Bélon (1518-64) published his octavo volume of 448 pages, entitled "De Aquatilibus," in which numerous (110) species of fishes of the Mediterranean were described, with tolerable figures, and with these is a creditable attempt at classification. At about this time Ulysses Aldrovandi, of Bologna, founded the first museum of natural history and wrote on the fishes it contained. In 1554-58, Ippolito Salviani (1513-72), a physician at Rome, published a work entitled "Aquatilium Animalium Historia," with good figures of most of the species, together with much general information as to the value and habits of animals of the sea.

More important than these, but almost simultaneous with them, is the great work of Guillaume Rondelet (1507-57), "De Piscibus Marinus" (1554-55), at first written in Latin, later translated into French and enlarged under other titles. In this work, 244 different species, chiefly from the Mediterranean, are fairly described, and the various fables previously current are subjected to severe scrutiny. Recognizable woodcuts represent the different species. Classification, Rondelet had none, except as simple categories for purposes of convenience. More than usual care is given to the vernacular names, French and Greek. He closes his book with these words:

"Or s'il en i a qui prennent les choses tant à la rigueur, qui ne veulent rien apparouver qui ne soit du tout parfait, je les prie de bien bon cueur de traiter telle, ou quelque autre histoire parfaitement, sans qu'il i ait chose quelconque à redire et la receverons é haut louerons bien vouluntiers. Cependant je scai bien, et me console . . . avec grand travail . . . qu'on pourra trouver plusieurs bones choses e dignes de louange ou proufit é contentement des homes studieux é à l'honneur é grandissime admiration des tres excellens é perfaits œuvres de Dieu."

And with the many "bones choses" of the work of Rondelet, men were too long satisfied, and it was not until the impulse of commerce had brought them face to face with new series of animals not found in the Mediterranean that the work of investigating fishes was again resumed. About 1640, Prince Moritz (Maurice) of Nassau (1604-79) visited Brazil, taking with him two physicians, Georg Marcgraf (1610-44) and Wilhelm Piso. In the great work "Historia Naturalis Brasiliæ," published at Leyden (1648), Marcgraf described about one hundred species, all new to science, under Portuguese names and with a good deal of spirit and accuracy. This work was printed by Piso after Marcgraf's death, and his colored drawings—long afterward used by Bloch—are in the "History of Brazil" reduced to small and crude woodcuts. This is the first study of a local fish fauna outside the Mediterranean region and it reflects great credit on Marcgraf and on the illustrious prince whose assistant he was.

There were no other similar attempts of importance in ichthyology for a hundred years, when Per Osbeck, an enthusiastic student of Linnæus, published (1757) the records of his cruise to China, under the name of "Iter Chinensis." At about the same time another of Linnæus' students, Fredrik Hasselquist, published, in his "Iter Palestinum" the account of his discoveries of fishes in Palestine and Egypt. More pretentious than these and of much value as an early record is Mark Catesby's (1679-1749) "Natural History of Carolina and the Bahamas," published in 1749, with large colored plates which are fairly correct except in those cases in which the drawing was made from memory.

At about the same time, Hans Sloane (1660-1752) published his large volume on the "Fishes of Jamaica," Patrick Browne (1720-90) wrote on the fishes of the same region, while Father Charles Plumier (1646-1704) made paintings of the fishes of Martinique, long after used by Bloch and Lacépède. Dr. Alexander Garden (1730-91), of Charleston, S. C., collected fishes for Linnæus, as did also Dr. Pehr Kalm in his travels in the northern parts of the American colonies.

With the revival of interest in general anatomy several naturalists took up the structure of fishes. Among these Günther mentions Borelli, Malpighi, Swammerdam, and Duverney. Other anatomists of later dates were Albrecht von Heller (1708-77), Peter Camper (1722-89), Felix Vicq d'Azyr (1748-94), and Alexander Monro (1783).

The basis of classification was first fairly recognized by John Ray (1628-1705) and Francis Willughby (1635-72), who, with other and varied scientific labors, undertook, in the "Historia Piscium," published in Oxford in 1686, to bring order out of the confusion left by their predecessors. This work, edited by Ray after Willughby's death, is ostensibly the work of Willughby with additions by Ray. In this work 420 species were recorded, 180 of which were actually examined by the authors, and the arrangement chosen by them pointed the way to a final system of nomenclature.

Direct efforts in this direction, with a fairly clear recognition of genera as well as species, were made by Lorenz Theodor Gronow, called Gronovius, a German naturalist of much acumen, and by Jacob Theodor Klein (1685-1757), whose work, "Historic Naturalis Piscium," published about 1745, is of less importance, not being much of an advance over the catalogue of Rondelet.

Far greater than any of these investigators, and earlier than either Klein or Gronow, was he who has been justly called the Father of Ichthyology, Petrus (Peter) Artedi (1705-35). Artedi was born in Sweden. He was a fellow student of Linnæus at Upsala, and he devoted his short life wholly to the study of fishes. He went to Holland to examine the collection of East and West Indian fishes of a rich Dutch merchant in Amsterdam named Albert Seba, and there at the age of twenty-nine he was, by accident, drowned in one of the Dutch canals. "His manuscripts were fortunately rescued by an Englishman, Cliffort," and they were edited and published by Linnæus in a series of five parts or volumes.

Artedi divided the class of fishes into orders, and these orders again into genera, the genera into species. The name of each species consisted of that of the genus with a descriptive phrase attached. This cumbersome system, called polynomial, used by Artedi, Gronow, Klein, and others, was a great advance on the shifting vernacular, of which it now took the place. But the polynomial method as a system was of short duration. Linnæus soon substituted for it the convenient, in fact inevitable binomial system which has now endured for 150 years, and which with certain modifications must form the permanent substructure of the nomenclature in systematic zoology and botany.

The genera of Artedi are in almost all cases natural groups, corresponding essentially equivalent to the families of to-day. Families in ichthyology were first clearly recognized and defined by Cuvier.

The following is a list of Artedi's genera and their arrangement:

ORDER MALACOPTERYGII.

• Syngnathus (pipefishes) (4 species).
• Cobitis (loaches) (3).
• Cyprinus (carp and dace) (19).
• Clupea (herrings) (4).
• Argentina (argentines) (1).
• Exocœtus (flying-fishes) (2).
• Coregonus (whitefishes) (4).
• Osmerus (smelts) (2).
• Salmo (salmon and trout) (10).
• Esox (pike) (3).
• Echeneis (remoras) (1).
• Coryphæna (dolphins) (3).
• Ammodytes (sand-launces) (1).
• Pleuronectes (flounders) (10).
• Stromateus (butter-fishes) (1).
• Gadus (codfishes) (11).
• Anarhichas (wolf-fishes) (1).
• Muræna (eels) (6).
• Ophidion (cusk-eels) (2).
• Anableps (four-eyed fish) (1).
• Gymnotus (carapos) (1).
• Silurus (catfishes) (1).

ORDER ACANTHOPTERYGII.

• Blennius (blennies) (5).
• Gobius (gobies) (4).
• Xiphias (swordfishes) (1).
• Scomber (mackerels) (5).
• Mugil (mullets) (1).
• Labrus (wrasses) (9).
• Sparus (porgies) (15).
• Sciæna (croakers) (2).
• Perca (perch and bass) (7).
• Trachinus (weavers) (2).
• Trigla (gurnards) (10).
• Scorpæna (scorpion-fishes) (2).
• Cottus (sculpins) (5).
• Zeus (john dories, etc.) (3).
• Chætodon (butterfly-fishes) (4).
• Gasterosteus (sticklebacks) (3).
• Lepturus (cutlass-fishes) (=Trichiurus) (1).

ORDER BRANCHIOSTEGI.

• Balistes (trigger-fishes) (6).
• Ostracion (trunkfishes) (22).
• Cyclopterus (lumpfishes) (1).
• Lophius (anglers) (1).

ORDER CHONDROPTERYGII.

• Petromyzon (lampreys) (3).
• Acipenser (sturgeons) (2).
• Squalus (sharks) (14).
• Raja (rays) (11).

In all 47 genera and 230 species of fishes were known from the whole world in 1738.

The cetaceans, or whales, constitute a fifth order, Plagiuri, in Artedi's scheme.

As examples of the nomenclature of species I may quote:

"Zeus ventre aculeato, cauda in extremo circinata." This polynomial expression was shortened by Linnæus to Zeus faber. The species was called by Rondelet "Faber sive Gallus Marinus" and by other authors "Piscis Jovii." "Jovii" suggested Zeus to Artedi, and Rondelet's name faber became the specific name.

"Anarhichas Lupus marinus nostras." This became with Linnæus "Anarhichas lupus."

"Clupea, maxilla inferiore longiore, maculis nigris carens: Harengus vel Chalcis Auctorum, Herring vel Hering Anglis, Germanis Belgis." This became Clupea harengus in the convenient binomial system of Linnæus.

The great naturalist of the eighteenth century, Carl von Linné, known academically as Carolus Linnæus, was the early associate and close friend of Artedi, and from Artedi he obtained practically all his knowledge of fishes. Linnæus, professor in the University of Upsala and for a time its rector, primarily a botanist, was a man of wonderful erudition, and his great strength lay in his skill in the orderly arrangement of things. In his lifetime, his greatest work, the "Systema Naturæ," passed through twelve editions. In the tenth edition, in 1758, the binomial system of nomenclature was first consistently applied to all animals. For this reason most naturalists use the date of its publication as the beginning of zoological nomenclature, although the English naturalists have generally preferred the more complete twelfth edition, published in 1766. This difference in the recognized starting-point has been often a source of confusion, as in several cases the names of species were needlessly changed by Linnæus and given differently in the twelfth edition. In taxonomy it is not nearly so important that a name be pertinent or even well chosen as that it be stable. In changing his own established names, the father of classification set a bad example to his successors, one which they did not fail to follow.

In Linnæus' system (tenth and twelfth editions) all of Artedi's genera were retained save Lepturus, which name was changed to Trichiurus. The following new genera were added: Chimæra, Tetraodon, Diodon, Centriscus, Pegasus, Callionymus, Uranoscopus, Cepola, Mullus, Teuthis, Loricaria, Fistularia, Atherina, Mormyrus, Polynemus, Amia, Elops. The classification was finally much altered: the Chondropterygia and Branchiostegi (with Syngnathus) being called Amphibia Nantes, and divided into two groups—Spiraculis compositis and Spiraculis solitariis. The other fishes were more naturally distributed according to the position of the ventral fins into Pisces Apodes, Jugulares, Thoracici, and Abdominales. The Apodes of Linnæus do not form a homogeneous group, as members of various distinct groups have lost their ventral fins in the process of evolution. But the Jugulares, the Thoracici, and the Abdominales must be kept as valid categories in any natural system.

Linnæus' contributions to zoology consisted mainly of the introduction of his most ingenious and helpful system of bookkeeping. By it naturalists of all lands were able to speak of the same species by the same name in whatever tongue. Unfortunately, ignorance, carelessness, and perversity brought about a condition of confusion. For a long period many species were confounded under one name. This source of confusion began with Linnæus himself. On the other hand, even with Linnæus, the same species often appeared under several different names; in this matter it was not the system of naming which was at fault. It was the lack of accurate knowledge, and sometimes the lack of just and conscientious dealing with the work of other men. No system of naming can go beyond the knowledge on which it rests. Ignorance of fact produces confusion in naming. The earlier naturalists had no conception of the laws of geographical distribution. The "Indies," East or West, were alike to them, and "America" or "India" or "Africa" was a sufficiently exact record of the origin of any specimen.

Moreover, no thought of the geological past of groups and species had yet arisen, and without the conception of common origin, the facts of homology had no significance. All classification was simply a matter of arbitrary pigeon-holing the records of forms, rather than an expression of actual blood relationship. To this confusion much was added through love of novelty. Different authors changed names to suit their personal tastes regardless of rights of priority. Amia was altered to Amiatus by Rafinesque in 1815 because it was too short a name. Hiodon was changed to Amphiodon because it sounded too much like Diodon, Batrachoides to Batrictius because βατράχος means a frog, not a fish, and other changes even more wanton were introduced, to be condemned and discarded by the more methodical workers of a later period. With all its abuses, however, the binomial nomenclature made possible systematic zoology and botany, and with the "Systema Naturæ" arose a new era in the science of living organisms.

In common with most naturalists of his day, the spirit of Linnæus was essentially a devout one. Admiration for the wonderful works of God was breathed on almost every page. "O Jehovah! quam ampla sunt opera Tua" is on the title-page of the "Systema Naturæ," and the inscription over the door of his home at Hammarby was to Linnæus the wisdom of his life. This inscription read: "Innocue vivito: Numen adest" (Live blameless: God is here).

The followers of Linnæus are divided into two classes, explorers and compilers. To the first class belonged his own students and others who ransacked all lands for species to be added to the lists of the "Systema Naturæ." Those men, mostly Scandinavian and Dutch, worked with wonderful zeal, enduring every hardship and making great contributions to knowledge, which they published in more or less satisfactory forms. To these men we owe the beginnings of the science of geographical distribution. Among the most notable of these are Pehr Osbeck and Fredrik Hasselquist, already noted; Otto Fabricius (1744-1822), author of an excellent "Fauna of Greenland"; Carl Peter Thunberg (1743-), successor of Linnæus as rector of the University of Upsala, who collected fishes about Nagasaki, intrusting most of the descriptive work to the less skillful hands of his students, Jonas Nicolas Ahl and Martin Houttuyn; Martin Th. Brünnich, who collected at Marseilles the materials for his "Pisces Massiliensis"; Petrus Forskål (1736-63), whose work on the fishes of the Red Sea ("Descriptio Animalium," etc.), published posthumously in 1775, is one of the most accurate of faunal lists, and one which shows a fine feeling for taxonomic distinctions scarcely traceable in any previous author. Georg Wilhelm Steller (1709-45), naturalist of Bering's expedition, gathered amid incredible hardships the first knowledge of the fishes of Alaska and Siberia, his notes being printed after his tragic death, by Pallas and Krascheninnikov. Petrus Simon Pallas (1741-1811) gives the account of his travels in the North Pacific in his most valuable volumes, "Zoographia Russo-Asiatica"; Johann Georg Gmelin (1709-55) with Samuel Theophilus Gmelin (1745-84), and Johann Anton Güldenstädt (1745-91), like Steller, crossed Siberia, recording its animals. Johann David Schöpf (1752-1800), a Hessian surgeon stationed at Long Island in the Revolutionary War, gave an excellent account of the fishes about New York.

Still other naturalists accompanied navigators around the globe, collecting specimens and information as opportunity offered. John Reinhold Forster (1729-98), with his son, John George Adam Forster (1754-94), and Daniel Solander (1736-81), a student of Linnæus, and Sir Joseph Banks (1743-1820), sailed with Captain James Cook. Philibert Commerson (1727-73) accompanied the explorer, Louis Antoine de Bougainville, and furnished nearly all the original material used by Lacépède. Other noted travelers of the early days were Pierre Sonnerat and Mungo Park.

Still other naturalists, scarcely less useful, gave detailed accounts of the fauna of their own native regions. Ablest of these was Anatole Risso, an apothecary of Nice, who published in 1810 the "Ichthyologie de Nice," an excellent work, afterward (1826) expanded by him into a "Histoire Naturelle de l'Europe Méridionalé."

Contemporary with Risso was a man of very different character, Constantine Samuel Rafinesque (1784-1842), who wrote at Palermo in 1810 his "Caratteri di Alcuni Nuovi Generi" and his "Ittiologia Siciliana." Later he went to America, where he was for a time professor in the Transylvania University at Lexington, Ky. Brilliant, erudite, irresponsible, fantastic, he wrote of the fishes of Sicily and later ("Ichthyologia Ohiensis," 1820) of the fishes of the Ohio River, with wide knowledge, keen taxonomic insight, and a hopeless disregard of the elementary principles of accuracy. Always eager for novelties, restless and credulous, his writings have been among the most difficult to interpret of any in ichthyology.

Earlier than Risso and Rafinesque, Thomas Pennant (1726-58) wrote of the British fishes; Otto Fredrik Müller of the fishes of Denmark; J. E. Gunner, Bishop of Thröndhjem, of fishes of Norway; Francis Valentijn (1660-1730), Jan Nieuhof (1600-1671), Renard, and Castour of the fishes of the Dutch East Indies; Duhamel du Monceau of the fisheries of France; Francesco Cette of the fishes of Sicily; José Cornide of the fishes of Spain; Ignacio Molina of the fishes of Chile; and Meidinger of those of Austria. Some of these writers lived before Linnæus. Others knew little of the Linnæan system, and their records are generally in the vernacular. Most important of this class is the work of Antonio Parra, "Descripcion de Diferentes Piezas de Historia Natural de la Isla de Cuba," published in Havana in 1787. In 1803, Patrick Russell gave a valuable account, non-binomial, of "Two Hundred Fishes Collected at Vizagapatam and on the Coast of Coromandel."

Papers on the fishes of Bering Sea and Japan by Wilhelm Theophilus Tilesius (1775-1835), are published in the transactions of the early societies of Russia. The collections of the traveler Krusenstern were recorded by Tilesius. Stephen Krascheninnikov (1786) wrote a history of Russia in Asia.

Other notable names among the early writers are those of Pierre Marie Auguste Broussonet, of Montpelier, whose work (1780), too soon cut short, showed marked promise; Fr. Faber, who wrote of the fishes of Iceland; E. Blyth, who studied the fishes of the Andamans; A. G. Desmarest, who made excellent studies of the fishes of Cuba; J. T. Kölreuter and Everard Home in the East Indies; Geoffrey Saint-Hilaire, who recorded the fishes of Egypt at the command of Napoleon. Others equally notable were B. A. Euphrasen, Iwan Lepechin (1750-1802), John Latham, W. E. Leach, George Montagu, C. Quensel, Jean-Antoine Scopoli, Peter Ascanius, Francois Etienne de la Roche (1789-1812), Hans Ström, M. Vahl and Zuieuw.

The compilers who followed Linnæus belonged to a wholly different class. These were men of extensive learning, methodical ways, sometimes brilliant, occasionally of deep insight, but more often, on the whole, dull, plodding, and mechanical.

Earliest of those is Antoine Gouan, whose "Historia Piscium" was published in Paris in 1770. In this work, which is of fair quality, only genera were included, and the three new ones which he introduces into the "System" (Lepadogaster, Lepidopus, and Trachypterus) are still retained with his definition of them.

Johann Friedrich Gmelin (1748-1804), a relative of the explorers of Siberia, published in 1788 a thirteenth edition of the "Systema Naturæ" of Linnæus, adding to it the discoveries of Forskål, Forster, and others who had written since Linnæus' time. This work was useful as bringing the compilation of Linnæus to a later date, but it is not well done, the compiler having little knowledge of the animals described and little penetration in matters of taxonomy. Very similar in character, although more lucid in expression, is the French compilation of the same date (1788), "Tableau Encyclopédique et Méthodique des Trois Règnes de la Nature," by the Abbé J. P. Bonnaterre. Another volume of the "Encyclopédie Méthodique," of still less merit, was published as a dictionary in Paris in 1787 by Réné Just Haüy. Another dictionary in 1817 even poorer was the work of Hippolyte Cloquet.

In 1792, Johann Julius Walbaum (1721-1800), a German compiler of a little higher rank, gathered together the records of all known species, using the work of Artedi as a basis and giving binominal names in place of the vernacular terms used by Schöpf, Steller, Pennant, and Krascheninnikov.

Far more pretentious and more generally useful, as well as containing a large amount of original material, is the "Ichthyologia" of Mark Eliezer Bloch, published in Berlin in various parts from 1782 to 1785. It was originally in German and divided into two portions—"Oeconomische Naturgeschichte der Fische Deutschlands" and "Naturgeschichte der auslandischen Fische." Bloch was a Jewish physician, born at Anspach in 1723, and at the age of fifty-six began to devote himself to ichthyology. In his great work is contained every species which he had himself seen, every one which he could purchase from collections, and every one of which he could find drawings made by others.

That part which relates to the fishes of Germany is admirably done. In the treatment of East Indian and American fishes there is much guesswork and many errors of description and of fact, for which the author was not directly responsible. To learn to interpret the personal equation in the systematic work of other men is one of the most delicate of taxonomic arts.

After the publication of these great folio volumes of plates, Dr. Bloch began a systematic catalogue to include all known species. This was published after his death by his collaborator, the philologist, Dr. Johann Gottlob Schneider. This work, "M. E. Blochii Systema Ichthyologia," contains 1519 species of fishes, and is the most creditable compilation subsequent to the death of Linnæus.

Even more important than the work of Bloch is that of the Comte de La Cépède, who became with the progress of the French Revolution, "Citoyen Lacépède," his original full name being Bernard Germain Etienne de la Ville-sur-Illon, Comte de La Cépède. His great work, "Histoire Naturelle des Poissons," was published originally in five volumes, in Paris, from 1798 to 1803. It was brought out under great difficulties, his materials being scattered, his country in a constant tumult. For original material he depended largely on the collections and sagacious notes of the traveler Commerson. Dr. Gill sums up the strength and weakness of Lacépède's work in these terms:

"A work by an able man and eloquent writer even prone to aid rhetoric by the aid of the imagination in absence of desirable facts, but which because of undue confidence in others, default of comparison of material from want thereof and otherwise, and carelessness generally is entirely unreliable."

The work of Lacépède had a great influence upon subsequent investigators, especially in France. A considerable number of the numerous new genera of Rafinesque were founded on divisions made in the analytical keys of Lacépède.