In the Diporpa condition of Diplozoon there are two supernumerary hooks, associated with a dorsal sucker at the centre of the body, and it is by means of these organs that a conjugation between two such juvenile forms is effected. These two individuals become organically united for life, after the fashion of the Siamese twins. After conjugation the sexual organs appear. In Onchotyle appendiculata the lower end of the body merges into a curious appendage, which is placed almost at a right angle with the body itself, and in this way, as Van Beneden justly remarks, the entire animal resembles a little hammer, the resemblance being very much heightened by the circumstance that one end of the appendage is cleft so as to correspond, as it were, with the notch which we employ in the action of nail-drawing. The Onchotyle appendiculata was first discovered by Kuhn attached to the gills of a dog-fish (Scillium catulus), but it has since been found ectoparasitically lodged upon other marine fishes. With the Gyrodactylidæ I include Van Beneden’s genus Calceostoma. The gyrodactyles have been classed with the Polystomidæ. Amongst the characters standing out most prominently are those having reference to peculiar hooks which project from the great sucking disk. In Calceostoma this mechanism is reduced to a single horny structure placed at the margin of the caudal sucker in the central line. In some Gyrodactyli the hooks are very numerous. In Gyrodactylus elegans the caudal sucker supports a pair of large laterally-curved hooks, which are placed back to back in the centre of the disk, being connected at their upper ends by a supplementary semi-lunar bar. A series of tentacles serve to increase the prehensile action of the sucker. In many species the males are supplied with accessory horny developments. The genus Gyrodactylus has been studied by Nordmann, Von Siebold, G. Wagener, Van Beneden, and especially by Wedl, who records the following results:—(a.) “Gyrodactylus is found on the gills of fresh-water fishes under numerous specific forms, G. elegans being also found by Creplin and Siebold on the fins. Moreover, as I have found nearly every species of fish supporting a particular gyrodactyle representative, it would seem that each finny creature supplies its own Gyrodactylus. Sometimes two of them are parasitic upon the same gill, being frequently associated with Trichodinæ, as well as with the still unintelligible Psorospermiæ. (b.) The clasping apparatus at the posterior end of the body must—in an animal so soft and constantly exposed to the passage of regular currents—be comparatively strongly developed and accommodated to the peculiar dwelling-places, and probably the varying character of the latter supplies a reason why there should be so great a difference in the mechanism of the hooks belonging to the disk. (c.) The hooked apparatus affords a very valuable and mathematically precise means of diagnosis in the determination of species. This differentiation may be accomplished by observing whether there are two or four large hooks; whether there be one or two connecting portions, and by noticing their several forms and relations to one another; and whether, again, there are hooklets or not, remarking in the first instance their position, form, distribution, and so forth. (d.) The integument is sometimes wrinkled transversely, at other times appearing to be smooth. (e.) The muscular apparatus is, in certain cases, very strongly developed. In the majority of instances special muscles are inserted into the handles of the hooks, and they are also very frequently directed into the transverse muscles of the skin. In Gyrodactylus crassiusculus we find a protrusor penis and retractor palparum medius. (f.) Except in the case of G. elegans, four so-called eye-spots are observed at the anterior extremity of all Gyrodactyli. As Siebold says, they answer the purpose of light-refracting organs. The palpi, which in G. crassiusculus are seen to contain muscular bundles, appear to be retractile touch-organs, extending more or less prominently forward. (g.) Observations in regard to the alimentary canal are at present incomplete, for only in the case of G. cochlea did I find a single gullet demonstrable. (h.) Gyrodactylus becomes sexually developed, and cannot be regarded merely as a kind of ‘nurse.’”

So much for Wedl, whose views I have elsewhere recorded at great length. The genetic relations subsisting amongst the Gyrodactyles have given rise to much controversy. Observing the singular mode of reproduction in G. elegans, Von Siebold arrived at the conclusion that Gyrodactyles in general were only nurse-forms of some higher organism, and he pointed out, with undeniable accuracy, all the birth-stages of the young one as it apparently pullulated within the parent and subsequently emerged an almost perfect Gyrodactyle. Von Siebold also remarked that the so-called “daughter,” at the time of birth, nearly equalled the “parent” in respect of size, whilst, moreover, it contained within its interior another very young Gyrodactyle, or, in other words, a “grand-daughter.” Van Beneden interpreted these facts very differently. I have myself noticed the second generation, or daughter, to contain in its interior evidences of a third generation. This I observed in specimens obtained from the tails of Gasterostei caught in the Serpentine, Regent’s Park. Indications of the third progeny were seen whilst the daughter still resided within the body of the nurse-parent, and the so-called grand-daughter became much larger immediately after birth. In one instance the “daughter” commenced showing herself by a slight bulging at the centre of the parent’s body, whilst the integument of the latter yielded on all sides of the bud-like projection, and in such a manner as to convey the idea of a vaginal opening. There was an evident struggle on the part of the young one to free itself from the so-called parent envelope, but the tissues showed no signs of injury. On partial protrusion it was seen that the budding portion corresponded with the centre of the daughter’s body, and this, in a little while, assumed the aspect of a semicircular band. Subsequently the upper end became detached, the freed extremity being now recognised as the head. An interval elapsed before the broad posterior end of the animal could be disengaged, but immediately after this was effected the sides of the parent envelope closed in upon the opening, and all that remained was a small cavity or sac, indicating the position recently occupied by the daughter. Altogether the process occupied about five minutes. I carefully compared the so-called “parent” with the “daughter,” but in regard to size I can scarcely say which was the larger of the two. As before hinted, Van Beneden demurs altogether to Von Siebold’s views. He does not admit the parent to be a kind of “nurse,” he does not consider the primary young one to be a “daughter,” and, consequently, he does not regard the embryo seen within the latter as a “grand-daughter.” Van Beneden says:—“According to our researches there is here a false interpretation; the little daughter is lodged within the side of its pretended mother, and not in its interior; instead of being its mother, it is its sister; there is a difference of shape because there is a difference of age; the Gyrodactyles are viviparous, and as among the Trematodes the eggs are formed one by one, one embryo is scarcely formed when another commences its evolution, and the egg-deposition is effected even whilst the embryo is being produced. The Gyrodactyles are therefore viviparous worms, which beget a single embryo at a time, as those of the trematode group, to which they are allied, beget a single egg at a time, and before the first embryo is expelled another is already partly developed. There, we believe, lies the correct interpretation of that phenomenon; instead of a bud it is an embryo, which has escaped from an egg. Here, therefore, we have no phenomenon of alternate generation or of digenesis, as Von Siebold supposes, but a simple viviparous reproduction.”

Passing on to notice the cestodes of fishes, I may remark that they often display characters very distinctive from those inhabiting birds and mammals, being commonly furnished with special tentacular hook-appendages employed as supplementary organs of boring and anchorage. In the cartilaginous sharks and rays these cestodes are remarkably abundant, and in certain osseous species they are scarcely less frequent. The only noteworthy kinds of fish which are commonly free from the invasion of tapeworms are the sturgeons, blennies, gobios, mullets, sparoids, and Sciænæ. Some few of them are infested by Ligulæ, Caryophyllæi, &c. Cuttle fishes harbor a great variety of tapeworm-larvæ, forming one of the chief sources whence sharks and rays obtain the same parasites destined to arrive at sexual maturity within their own bodies.

Among the most interesting cestodes of fishes we may reckon the pit-headed tapeworms and their allies (Bothriocephalidæ). One of the most common species is Both. proboscideus which is found, often in considerable numbers, lodged within the pyloric appendages of the salmon (Salmo salar and S. hucho). It acquires a length of two feet. When in large numbers it cannot fail to prove injurious to the bearer. In this connection also must be mentioned B. nodosus. In the adult state this worm infests a great variety of water-birds (herons, gulls, and divers), but in the young or sexually-immature tænioid condition it is a frequent inhabitant of sticklebacks (Gastereosteus aculeatus and G. pungitus), being also found in the salmon and in the bull-head, or father-lasher (Cottus scorpio). The immature tapeworm was formerly considered a separate species (B. solidus). Some years back Creplin discovered the connection subsisting between the two forms, and re-described the species in its two conditions under the name of Schistocephalus dimorphus, but it was reserved for Von Siebold to explain the full nature of this relationship. In his essay on “Tape and Cystic Worms” he shows that it is not until the worm reaches the intestine of the ultimate host that its segments acquire sexual completeness. As Von Siebold observes, “the extent of development in each individual will be found to be in proportion to the time the parasite has passed in the bird’s alimentary canal after its passive immigration.” A similar instance, it is added, “occurs in the case of the Ligula simplicissima, infesting the abdominal cavity of various species of carp, whose sexual organs are, and remain, undeveloped as long as the worm resides within the fish; whilst, when the latter is eaten by ducks, divers, waders, and other water-fowl, the entozoon being thus conveyed into their intestine, it attains perfect sexual development. In the older helminthological works the sexually-mature Ligula simplicissima is described under various specific names (L. sparsa, L. uniserialis, L. alternans, L. interrupta).” These results have been confirmed by later observers, but it is now usual to recognise the sexually-mature worm as the Ligula monogramma of Creplin. In 1876 Dr Duchamp published his beautiful memoir on this subject, treating the entire question exhaustively and adding important experimental details. M. Duchamp gives a list of about twenty species of fish that are infested by the immature worm, and amongst these the Cyprinidæ play by far the most conspicuous part. M. Duchamp has recorded a fatal piscine epizoöty amongst tenches (Tinca vulgaris), occurring in the ponds of La Bresse. This is produced by Ligula simplicissima, which escapes by an aperture formed near the vent of the infested fish. M. Duchamp also gives important anatomical and embryological details, but the especially interesting part of his memoir refers to his feeding experiments, seven in number. He succeeded in rearing L. monogramma in the domestic duck, by feeding this bird with examples of L. simplicissima obtained from the abdomen of the tench (Tinca vulgaris). The interest of these experiments does not cease here, since they afford a probable clue to the source of human Bothriocephali, which in nearly all essential points of structure correspond with the Ligules. As remarked in the first part of this work, Leuckart long ago pointed to the Salmonidæ as probably furnishing the intermediate host of this worm; and he disproved the views of Knoch, of Petersburg, who thought he had reared Bothriocephalus latus in the dog in a direct manner. I have already called attention to the opinion of Dr Fock, of Utrecht, who thinks the human bearer may become infested by the consumption of the little fresh-water bleak (Leuciscus alburnus). From the observations of Dr Bertolus, it is extremely probable that our Bothriocephalus latus is the sexually-mature condition of Ligula nodosa infesting the abdominal cavity and pyloric appendages of the common trout (Salmo trutta).

Another cestode of general interest is the Tricuspidaria (Triænophorus) nodulosus, infesting many of our fresh-water fishes. It varies in length from one to two feet. The segmentation of the strobila is very indistinct, but the reproductive organs occur at regular intervals. All parts of the body are extremely contractile, especially the head. The tricuspid hooks support thin chitinous laminæ, which connect the two lateral horns of each hook to the central apophysis. The object of this arrangement is to afford additional security to the prong-like processes. Van Beneden appears to think it an error that the cusps of the hooks should have been figured in ‘Règne Animal’ as directed forwards, and he has drawn the hooks with the points downwards. In regard to the calcareous corpuscles, narrow vessels may be easily recognised passing off continuously from the capsules in closing the particles. These vascular prolongations are single, having their course directed towards the epidermis; doubtless they open at the surface, but I did not detect any aperture. I have figured the tubes in my ‘Entozoa’ (p. 132). Dr Guido Wagener figures similar structures as occurring in Cercaria macrocerca.

Various species of Tetrarhynchus dwell in the bodies of sharks and rays, whilst their larvæ inhabit fishes on which the plagiostomi feed. Immature tetrarhynchs occur in cuttle-fishes, but they are most abundant in such fish as the cod, haddock, turbot, whiting (Fig. 81), flounder, sole, gurnard, mackerel, mullet, and conger-eel. A tænioid scolex constantly infests the muscles and viscera of the great sunfish. The tetrarhynchs differ from one another as regards the form of their proboscides and the relative number and disposition of the hooks. I must refer to my ‘Entozoa’ for a full description, with figures, of a larval tetrarhynch from the wall of the intestine of a haddock. Some Tetrarhynchi exhibit a very complex armature, as may be seen in Tetrarhynchus longicollis infesting the tope or penny dog-fish (Galeus vulgaris). In this species the hooks are uniform in size, and arranged in spirally disposed circles carrying from twenty to thirty hooks each. In the tetrarhynch from the whiting the hooks show much irregularity both as regards size and arrangement. A remarkable scolex infests the sun-fish (Orthagoriscus mola); it is a true tetrarhynch, but has been variously classed. According to view all the following titles refer to this parasite:—Gymnorhynchus reptans, Rudolphi; G. horridus, John Goodsir; Acanthorhynchus reptans, Diesing; Bothriorhynchus continuus, Van Lidth de Jeude; Bothriocephalus patulus, Leuckart; Acanthocephalus elongatus, Rudolphi; A. macrourus, Bremser; Floriceps saccatus, Cuvier; F. elongatus, Blainville; Scolex gigas, Cuvier; Tetrarhynchus reptans, Cobbold.

Five or six examples of the sunfish have been examined by me in the fresh state, all of them being infested by tetra­rhynchs. In the fish here drawn (fig. 82) the liver and lateral muscles were extensively tunnelled by the parasite. In all instances the anterior part of the worm was found surrounded by a thick, clear, transparent cyst, which gradually diminished in thickness towards the tail. When liberated from its investing capsule the head of the worm presents a quadrilateral figure, each lateral half being furnished with a bipartite facet. The retractile boring organs are club-shaped, each supporting about 1600 hooks. Nearly all the hooks display a uniform length and thickness, but at the lower part of each proboscis there are two conspicuous circles, the hooks of which are at least twice as large as the others. The joints of the immature strobile are well formed, but exhibit no trace of sexual organs. If it be asked “what is the object of this perpetual tunnelling,” and “does the boring cause suffering to the host,” I reply:—“The object of tunnelling is apparently twofold; first, that the parasite may constantly obtain fresh nourishment; and secondly, that it may acquire another residence.” It furnishes an example of a parasite perpetually striving to perform an act which it cannot accomplish; for, in order to arrive at sexual maturity, it must wait until the sunfish is devoured by a shark. In regard to the question as to the boring action giving rise to pain, one cannot, of course, speak with absolute certainty. When there are many parasites occupying the liver, or other important viscera, then, doubtless, they create pain, and cause decay of the organs infested; thus they enfeeble the vital powers of the host. At such a time the sunfish would be easily overcome by its natural enemies, and be the first to succumb in the struggle for existence. These wandering tetrarhynchoid scolices never escape the body of the intermediate host until they are passively transferred into the alimentary canal of the ultimate entertainer. In the sharks and rays they acquire sexual maturity. From these animals the proglottides pass into the water in the ordinary way. The ova are subsequently swallowed by sunfishes and other intermediate hosts, within whose stomachs the six-hooked embryos are liberated, and the scolices become developed in the ordinary manner. As obtains in Cysticercus fasciolaris of the mouse the scolex of Tetr. reptans becomes tænioid. I have seen the liver of an adult sunfish so infested by these parasites that the whole organ might be fitly described as a mere bag of worms, the immature strobiles being inextricably coiled together and defying separation. One of the parasites which I removed from this particular fish is preserved in the Hunterian Collection.

In reference to the nematoids of fishes I can say but little. They are excessively abundant; sexually-immature filariæ being found in almost every marine fish that one examines. Even at our dinner and breakfast tables nothing is more common than to observe the little Filaria piscium spirally coiled within the tissues of herrings, haddocks, cod-fish, and whiting. All the sexually-immature nematoids are, as it were, waiting to be passively transferred to their ultimate hosts. These final bearers are usually either fishes, birds, cetacea, or seals. Amongst fresh-water fishes the Cucullanidæ play an important rôle. These parasites closely resemble the strongyloid Sclerostomata, but the absence of a true bursa seems to justify their separation into a distinct family. In most of them the body is truncated in front and much narrowed or drawn out posteriorly. The head is, broad and globular, and furnished with a powerful muscular pharynx. The mouth is seldom round; it is often subterminal, opening by a transverse slit. The tail of the male is recurved, and usually supplied with membranous winged appendages; sometimes there is a pre-anal sucking disk. In the female the tail is simple, and more or less sharply pointed.

The facts relating to the development of these parasites are especially interesting as having afforded Leuckart and Fedschenko a clue to what obtains in the guinea-worm (Dracunculus). The Cucullanus of the perch (C. elegans) is a viviparous species. The embryos are supplied with little boring teeth, or styles, which enable them to perforate the bodies of entomostracous crustaceans. Having in a direct manner gained access to the perivisceral cavity of Cyclops, they remain coiled within the intermediate bearer until it has been pursued, captured, and transferred to the stomach of the ultimate or piscine host. Once liberated within the stomach of the fish the young Cucullani soon acquire sexual maturity.

The acanthocephalous Echino­rhyn­chi are very abundant in fishes. They also, like the Cucullani, require a change of hosts in order to ensure the continuance of the species. No less than six species of Echinorhynchi are known to infest the trout (Salmo fario). As many as four species likewise infest the eel (Anguilla); the same number of distinct forms being also found in the turbot (Rhombus) and ling (Lota), whilst three species may be met with in the common sole (Solea). What we at present know respecting the mode of development of Echinorhynchi infesting fishes is principally due to the researches of Leuckart. Some years back Dr Guido Wagener supplied admirable illustrations of the eggs and embryos of Echinorhynchi, but he was erroneously led to conclude that the larvæ were developed in a direct manner. The notion of a simple metamorphosis was entirely disproved by the experiments of Leuckart, who found the growth and development of the young to be accompanied by a true alternate generation. He showed this to obtain in Echinorhynchus proteus, a species abundant in the trout and in many other fresh-water fishes. The embryo of this parasite is broad and obliquely truncated at the ventral surface anteriorly, being gradually narrowed to a blunt point posteriorly, and at the front part, on each side of the middle line, there are five or six spines biserially disposed. Similar characters are seen in E. filicollis. Prof. Leuckart introduced a number of eggs into a vessel of water containing several small crustaceans (Gammarus Pulex). These little animals readily swallowed the ova, and in a few days the embryos were found emerging from their shells, boring their way through the intestinal walls, then passing into the general cavity of the body, and even into the appendages themselves. During the next fourteen days the embryos within the Gammari exhibited an increase of size; and in course of the third week a further metamorphosis caused the embryos to assume the readily recognisable characters of a young Echinorhynchus. Thus, in Leuckart’s own words, “the ultimate animal arises in the interior of the primordial body, by a process which presents so close an analogy with the production of an embryo, and, consequently, with the act of generation, that one feels inclined at once to identify it with such an act, and therefore, also, to regard the Echinorhynchus as exhibiting an alternation of generation in its mode of development rather than a metamorphosis.”

The young Echinorhynchus afterwards grows rapidly, its several internal organs, proboscideal sac, and muscular apparatus, gradually coming into view. At last the young entozoon completely fills the interior of the embryo, the latter having scarcely undergone any change, and still remaining, of course, within its crustacean host. What may be regarded as even more extraordinary is the circumstance that the embryonic body next becomes firmly adherent to the young Echinorhynchus, thus ultimately forming the true integument of the adult Echinorhynchus. The original skin of the embryo, however, is cast off “as soon as the Echinorhynchus occupies the whole interior of the embryo.” After this the sexual differences become clearly established. Leuckart remarks that the passage of the young Echinorhynchi into their ultimate host is probably unattended by any striking changes, whilst the metamorphosis of the embryo, as thus far detailed, occupies a period of about six weeks. In general the crustacean hosts appear to suffer little from the borings of the embryo parasites, but when the latter have assumed the Echinorhynchus-condition and happen to be particularly numerous they not unfrequently prove fatal to the unsuspecting Gammari. After their transference to the intestine of the ultimate host a period of about one week more is required for the completion of their development.

From the large number of species of Echinorhynchi infesting our fresh-water fishes, they present quite a feature of piscine parasitism. Almost every perch, chub, carp, pike, barbel, bream, or roach that one opens is found to have its intestines occupied by parasites which exhibit a light yellow color. These are Echinorhynchi, the common forms being E. proteus, E. angustatus (Fig. 84, No. 1), E. clavæceps, E. globulosus, and E. tuberosus. In the Salmonidæ, besides several of the above, we may also find E. clavula, E. fusiformis, and E. pachysomus. As a group these parasites are more attractive looking than most other helminths, and they will well repay the zoological collector. The species infesting marine fishes are almost as numerous as those found in fresh-water hosts.

Bibliography (No. 59).—(Anonymous), “Note by ‘An Inquirer’ respecting Worms in Fish,” in the ‘Lancet,’ March 7, 1868, p. 336.—Baer, K. E. von, “On the Tapeworms found in the Waters of the Pregel by Linneus,” from the German, in ‘Edin. New. Phil. Journ.,’ 1829, p. 374, and in the ‘Edin. Nat. and Geo. Sci. Journ.,’ 1829–30, p. 311; also from the ‘Trans. of Nat. Soc. of Dantzig,’ in the ‘Lancet,’ 1829.—Badcock; see Slack.—Baird, ‘British Entomostraca,’ London, 1850.—Beneden, J. P. van, “Les vers cestoides,” ‘Mém. de l’Acad. Roy. de Belg.,’ tom. xxv, 1850.—Idem, ‘Mém. sur les vers intest.,’ Paris, 1858.—Idem, “On Echinobothrium,” in ‘Bull. de l’Acad. de Brux.,’ 1849.—Idem, (with Hesse), ‘Rech. sur les Bdellodes ou Hirudinées et les Trématodes marins,’ 1863–65.—Idem, ‘Rech. sur les Turbellaries,’ 1861.—Idem, “On a new Lerneonema,” ‘Bull.,’ l. c., 1851, and in ‘L’Institut,’ 1851.—Bertolus, ‘Mém. sur le développement du Dibothrium latum (Bothriocéphale de l’homme),’ App. to Dr Duchamp’s work quoted below.—Bosc, ‘Hist. Nat. des Vers,’ 1802, p. 271.—Bradley, C. L., “On the occurrence of Gyrodactylus on Sticklebacks,” ‘Proc. Linn. Soc.,’ 1861.—Brullé, “Note on the Reproduction of Ligula,” from ‘Comptes Rendus,’ in ‘Ann. Nat. Hist.,’ 1855.—Chatin, ‘On Amphibdella torpedinis from the Gills’ (l. c., Bibl. No. 57).—Chavannes, “On Fluke-larvæ from Coregonus,” in ‘Bull. de la Soc. Vaud. des Sci. nat.,’ tom. iii.—Claparède, E., “Ueber die Gattung Tetracotyle,” &c., in ‘Zeitsch. f. wiss. Zool.,’ 1857, s. 99 et seq.—Cobbold, “The Sunfish (Orthagoriscus) as a Host,” ‘Intell. Observer,’ Sept., 1862.—Idem, “Notes on the Calcareous Corpuscles of Tricuspidaria,” ‘Quart. Journ. Micr. Sci.,’ 1859.—Idem, “Notes on Tricuspidaria and Pentastoma,” ibid., 1859.—Idem, “Note on Gyrodactylus elegans,” ibid., 1862; see also Wedl.—Idem, “On Distoma clavatum from the Sword-fish,” ‘Proc. Linn. Soc.,’ 1867 (Zool. Sect., p. 200).—Idem, “Tapeworms in Trout,” letter to the ‘Field,’ July 26, 1873; see also F. Francis (below).—Idem, “Remarks on the Entozoa and Ectozoa of Fish,” the ‘Veterinarian,’ Oct., 1867, p. 671.—Idem, “On Agamonema crenilabri,” in ‘Science Gossip,’ 1876; see W. W. Wilson.—Idem, in ‘Linn. Trans.,’ 1858.—Idem, ‘Note on Parasites from the Wolf-fish (Annarhicas) and Lump-sucker (Cyclopterus), collected by Mr Devis’ (l. c., Bibl. No. 57).—Idem, “Descr. of the Scolex of a Tetrarhynchus,” in a paper on ‘Parasite Larvæ,’ ‘Intell. Observer,’ 1863.—Idem, “Synopsis of the Distomidæ,” ‘Proc. Linn. Soc.’ (Zool. Div.), 1860.—Idem, “Remarks on Bothriocephalus latus, in relation to Dr Fock’s supposition that the Bleak (Leuciscus alburnus) is concerned in its Production,” the ‘Veterinarian,’ July, 1878.—Cornalia, E., ‘Sopra una nuova specie di Crostacei Siphonostomi (Gyropeltis doradis),’ Milano, 1859.—Coughtrey, M., “On the absence of Tapeworm in the Salmon-trout of New Zealand,” letter to the ‘Otago Daily Times,’ dated from the Otago University, Dec. 6, 1875.—Diesing, ‘Vierzehn Arten von Bdellideen,’ Wien, 1858; see also ‘Revisions,’ quoted in Bibl. No. 58.—Donnadieu, A., “Étude sur les Ligules,” in ‘Archives Zool. Expériment.,’ 1876.—Duchamp, G., ‘Recherches anat. et physiol. sur les Ligules,’ Paris, 1876; see also Bertolus.—Fock, ‘The Bleak as a source of the Broad Tapeworm.’ See Cobbold.—Francis, F., “Tapeworm in Fish” (with report by myself), in the ‘Field,’ June 28, 1873.—Idem, in the ‘Field’ for July 12, 1873.—Garsin, ‘Histoire de l’Acad. des Sci.,’ Paris, 1730, p. 44.—Goodsir, J., “On Gymnorhynchus horridus, a new Cestoid Entozoon,” ‘Edin. New Phil. Journ.,’ p. 9, 1841.—Houghton, W., “On the occurrence of Gyrodactylus elegans in Shropshire,” ‘Ann. Nat. Hist.,’ 1862.—Huxley, “Note on Gyrodactylus,” ‘Proc. Roy. Inst.,’ April 20, 1852, and ‘Edin. New Phil. Journ.,’ 1852, p. 172.—Knoch, J., ‘Entwickelungsgeschichte d. Both. proboscideus,’ 1862.—Knox, J. F., “Note respecting the occurrence of a peculiar Microscopic Entozoon in the Textures of the Herring,” ‘Lancet,’ 1838.— Kölliker, “Zwei neue Distomen,” ‘Ber. v. d. K. Zoot. Anstalt zu Würzburg,’ 1849.—Idem, ‘Ueber Tristoma,’ ibid., 1849.—Leidy, J., “Notice of a Tetrarhynchus (T. tenuicaudatus) in the Remova;” ‘Proc. Acad. N. S. Philad.,’ Oct. 15, 1878; and in ‘Ann. Nat. Hist.,’ Feb., 1879.—Leydig, “Ueber Argulus,” ‘Sieb. und Köll. Zeitsch.,’ 1850.—Maddox, R. L., “Some Remarks on the Parasites found in the Nerves (and other parts) of the Common Haddock (Morrhua æglefinus),” ‘Trans. of the Roy. Micr. Soc.,’ 1867, p. 87.—Menzies, ‘Linn. Trans.,’ 1790, p. 187.—Miescher, “On Filaria piscium,” &c., in ‘Excerpta Zoologica,’ communicated by Dr Frances, in ‘Ann. Nat. Hist.,’ 1842.—M’Intosh, W. C., “Notes on the Food and Parasites of the Salmo salar of the Tay,” ‘Proc. Linn. Soc.,’ 1863; repr. in the ‘Zoologist,’ Feb., 1864.—Müller, J., “Note on a Parasitic Formation (Gregarina) in the Pike, with a statement from his ‘Neurologie der Myxinoiden,’ that Diplostomum rachineum is to be found alive under the cerebral membranes of Petromyzon fluviatilis,” from ‘Müller’s Archiv,’ in ‘Micr. Journ. and Struct. Record,’ p. 20, 1842.—Nardo, in ‘Heisinger’s Zeitsch.,’ 1827, s. 68, and in ‘Isis,’ 1833, s. 523.—Olsson, P., “Researches on the Flukes and Tapeworms chiefly of Marine Fishes,” ‘Entozoa, iakttagna hos Skandanaviska Hafsfiskar,’ Lund (aftr. ur ‘Lunds Univ. Årsskrift,’ tom. iii, iv), 1867–68.—Owen, ‘Zool. Soc. Trans.,’ 1835, p. 382.—Pallas, ‘Spicilegia Zoologica,’ fasc. x, p. 18, 1774.—Siebold, C. von, ‘Band und Blasenwürmer,’ s. 41, Huxley’s edit., p. 32.—Idem, “On Diplozoon paradoxum,” from ‘Zeitsch. f. wiss. Zool.’ (by Huxley), in ‘Ann. Nat. Hist.,’ 1851.—Idem, “Ueber den Generationswechsel der Cestoden nebst einer Revision der Gattung Tetrarhynchus,” ‘Zeitschr. f. wiss. Zool.,’ 1850, s. 198.—Idem, “Gyrodactylus, ein ammenartiges Wesen,” ibid., 1849.—Slack, H. J., “On Bucephalus polymorphus,” in ‘Monthly Microsc. Journ.,’ April, 1875, p. 141.—Van Beneden (see Beneden).—Verrill, A. E., “On the Parasitic Habits of the Crustacea,” from ‘American Naturalist,’ in ‘Scientific Opinion,’ Aug. 4, 1869, p. 185.—Idem, “New Flukes (Tristoma læve and T. cornutum) from the Mouth and Gills of Tetrapturus albidus,” ‘American Journ. of Science,’ p. 40, 1875.—Von Baer (see Baer).—Von Siebold (see Siebold).—Wagener, R. G., “Helminth. Bemerkungen,” in ‘Sieb. und Köll. Zeitsch.,’ 1857.—Idem, “Enthelminthica,” ‘Müller’s Arch.,’ 1851.—Idem, “Ueber Eingeweidewurm (Amphiptyches) in Chimæra monstrosa,” ‘Müll. Arch.,’ 1852.—Idem, ‘Beiträge zur Entw.-Gesch. der Eingeweidewürmer (Preisschrift),’ 1857.—Wedl, “On Gyrodactylus” (see reference to my paper on ‘G. elegans’), ‘Quart. Journ. Micr. Sci.,’ 1862; trans. from his ‘Anhang,’ “Ueber die Gattung Gyrod.,” to ‘Anat. Beobachtungen ueber Trematoden,’ Wien, 1858.—Idem, ‘Hæmatozoa in Fishes,’ &c. (l. c., Bibl. No. 58).—Wigham, R., “Note on Holostomum cuticola from Roach and Bream,” ‘Ann. Nat. Hist.,’ p. 235, 1851.—Wilson, W. W., “On a Parasitic Worm infesting a Marine Fish (Crenilabrus rupestris),” in ‘Science Gossip,’ Jan., 1876.—Yarrell, W., “Note on Tristoma coccineum,” in his work on ‘Brit. Fishes,’ vol. ii, p. 353, 1836.

Part IV (Evertebrata).

Since a large proportion of all those helminths that require a change of hosts must needs pass into the bodies of insects, crustaceans, mollusks, or other evertebrated animals, it is evident that these lower creatures are almost as liable to be infested by parasites as the vertebrates themselves. As a rule, no doubt, the parasitic forms infesting individual evertebrated hosts are not numerous; nevertheless the water-snails form a noteworthy exception. Thus, some ten different species of parasite are found either in or upon the common Planorbis corneus; whilst Lymnæus stagnalis, Paludina vivipara, and P. impura, each support at least a dozen species. Of course, the parasites are not sexually mature, since nearly all of them are Cercariæ or larval trematodes. Snails, oysters, mussels, whelks, and other mollusks afford harbour and anchorage to a variety of parasites and messmates; but, fortunately, few or it may be none of the strictly human parasites require to pass through these intermediate bearers. Distoma crassum is possibly an exception. Save the cuttle-fishes, not many evertebrated animals are infested by sexually-mature worms. One of the most notable exceptions is that of a nematoid infesting bees. This worm was known to John Hunter, who spoke of it as “the animal that breeds in the humble bee.” In the year 1836, M. Léon Dufour first applied the term Sphærularia to this remarkable worm, which he discovered in the abdominal cavities of two species of bee (Bombus terrestris and B. hortorum). The worm was subsequently found by Von Siebold in two other species of bee (B. muscorum and B. sylvarum), but it remained for Sir John Lubbock to demonstrate that this parasite not only infests these insects, but also Bombus lucorum, B. lapidarius, B. pratorum, B. subterraneus, and Apathus vestalis. I possess specimens from Vespa vulgaris and V. rufa. Sir J. Lubbock and Mr. Cole have separately given full anatomical descriptions of the worm. According to Lubbock the so-called female is about an inch in length, of a whitish color, and 1/15″ in thickness, being bluntly pointed at either extremity. Sphærularia is everywhere covered by small warts or button-like projections, in all numbering about 800. The warts are transparent, each, according to Lubbock, projecting from 4/1000″ to 6/1000″ above the general surface of the integument. There is neither mouth, œsophagus, intestine, nor anus; but in their place a large fatty mass or corpus adiposum. Sir J. Lubbock remarks that this peculiar organ “is homologous, not with the whole intestinal canal of nematodes, but only with the intestine; and we find, in fact, that in Gordius the œsophagus is very short, and opens at once into the anterior end of the corpus adiposum; so that to pass from this genus to Sphærularia it would be necessary to shorten the œsophagus a little more, and then the wall of the corpus adiposum would be immediately attached to that of the body. So far, therefore, as concerns the corpus adiposum and the œsophagus, Sphærularia agrees neither with Gordius nor Mermis, nor, indeed, with one more than the other; since, if it agrees with Mermis albicans in the double series of large fat cells, it has no œsophagus, and in this respect more nearly resembles Gordius.” The reproductive organs consist of a single ovary, uterus, and terminally situated vulva. These organs in the full-grown females contain ova in all stages of development up to the condition of advanced yolk segmentation; but it does not appear that embryonic formation takes place whilst the eggs are still in utero. “The young animals are born soon after the eggs are laid. They are about 1/60″ in length, and 1/2500″ in diameter at the broadest part. Before Sir J. Lubbock conducted his inquiries the so-called male appears to have been overlooked. The male, if male it be, is extremely minute; that is to say, about 28,000 times smaller than the female.” Notwithstanding this very circumstantial account based on Lubbock’s determinations, Schneider has sought to show that the facts have been entirely misinterpreted. What Lubbock regards as the male worm is, in Schneider’s opinion, a female, whilst the so-called female is nothing more than a gigantic prolapsed uterus which has become many thousand times larger than the body of the worm whence it proceeded. It must be allowed that Schneider’s description and accompanying figures are very convincing. When revising the entozoa of the Hunterian Collection in 1866 I explained the specimens and dissections in accordance with Lubbock’s views. In the following year Prof. Huxley in his College Lectures supported the view of Schneider, but in his recently published manual the opinions of the Berlin helminthologist are not so much as alluded to.

Another point of special interest in connection with the parasites of insects concerns the development of Mermis albicans. At or near the time of the maturation of the ova, the parent worm, hitherto lodged within the body of some insect, buries itself in the soil. It commences its migration by boring its way out of the body of the host. Some difference of opinion exists as to the condition of the parent at the time of its wandering, for Von Siebold asserted that it quitted its parasitical mode of life “in order to become sexually mature away from the animal” infested; whereas Van Beneden states that the embryos are always formed at the time of the wandering.

From Von Siebold’s experiments it would appear that incompletely developed Mermes can become mature whilst still in the soil; but the normal condition requires the wandering to commence, as we have said, at or near the full time of embryonal development. The embryos are reproduced viviparously, and being set free, they pass a certain period of their existence in the soil. Here they grow rapidly, acquire sexual organs, and subsequently seek to “gratify their immigrative propensities,” as Von Siebold says, by selecting and penetrating the soft-bodied larvæ of lepidopterous and other insects. This entrance they accomplish by means of a sharply-pointed dentule or boring stylet, which at the time of disuse is concealed within the head. Having once gained access to the host they remain within its body until the caterpillar has become transformed into the perfect butterfly, or until their own sexual maturity is completed. Van Beneden thinks it probable that the males quit the host some time before the females, a view which, if correct, might alone account for the comparative scarcity of the males. According to Von Siebold, sexual congress occurs before the entrance of the worm into the caterpillar. This observation agrees with the generally admitted fact that hitherto no male Mermes have actually been detected in the bodies of insects. The Gordii, like Mermes, become free in damp earth and penetrate the bodies of certain insects or their larvæ. Some of them gain access to fishes. Like the free nematodes (Anguillulidæ), many of the Gordii will survive complete desiccation. The eggs of the mature worms are deposited in long agglutinated chains in water or damp situations.

I must conclude. In the body of this work will be found many notices of insect parasites that are awaiting transference to some vertebrate. I need only allude to the rôle of the mosquito, to that of the louse of the dog, and especially to that of the little myriapod (Glomeris) which, like the common glow-worm (Lampyris), possesses phosphorescent properties. I mention this again partly in correction of an entomological error (at p. 296) which escaped me at the time of going to press. Leidy has described a mature nematode (Ascaris infecta) from Passalus cornutus, and numerous Filariæ are known to infest insects (Blatta, Forficula, Phosphuga, &c., &c.). From an earwig I obtained a filaria nearly five inches in length.

We have seen that the larvæ of Dracunculus, Cucullanus, as well as those of other important nematodes, dwell in bodies of entomostracous crustacea, whilst those of Echinorhynchus attack the Gammari and their allies. The well-known Udonella caligorum attaches itself to crustacea that are themselves parasitic.

As many of the so-called free nematodes live in the slime of animals, Villot is of opinion that no very distinct line of demarcation can fairly be drawn between the parasitic and free species. This work, however, having dealt only with genuine parasites, I have purposely omitted any detailed account of the so-called free nematoids. I mention this lest it should be supposed that I had shown a studied neglect of the more or less remarkable labours of Bütschli, Bastian, Eberth, Linstow, Marion, Villot, Claus, De Man, Carter, and many others.

Bibliography (No. 60).—Bastian, H. C., “Monograph on the Anguillulidæ, or free Nematoids, marine, land, and freshwater, with description of 100 new species,” ‘Linnean Trans.’ for 1865, vol. xxv, p. 73.—Idem (see Bibliog. No. 2).—Idem, “Free Nematoids,” being an article in the ‘Popular Science Review’ for 1868, vol. vii, p. 163.—Brady, G. S., ‘Monograph of the free and semiparasitic Copepoda,’ London, 1878.—Bütschli, O., “Untersuchungen ueber freilebende Nematoden und die Gattung Chætonotus,” ‘Sieb. und Köll. Zeitschrift,’ 1876.—Carter, H. J., “On a Bisexual Nematoid Worm which infests the common House-fly (Musca domestica),” ‘Ann. Nat. Hist.,’ 1861, and in the ‘Bombay Med. and Phys. Soc. Trans.,’ new series, 1860.—Claparède (see Panceri).—Claus, C., ‘Beobachtungen ueber d. Organis. und Fortpflanz. v. Leptodera appendiculata,’ 1869.—Cobbold, “Note on Insect Parasites,” in ‘Rep. of Entomological Club,’ in the ‘Midland Naturalist,’ March, 1878, p. 80.—Cole, W., “Remarks on a Parasite of Humble Bees,” in ‘Journal of the Quekett Microscopical Club,’ 1875.—Dufour, L., “Sphærularia,” ‘Ann. des Sci. Nat.,’ 1836.—Dujardin, “On Mermis,” ‘Ann. des Sci. Nat.,’ 2e sér., tom. 18, p. 129.—Eberth (see Bibliog. No. 2).—Garner, R., “Note on a Distoma,” in his paper ‘On the Lamellibranchiate Conchifera,’ ‘Trans. Zool. Soc.,’ 1841.—Ghaleb, O., “Observations and Experiments on the Migrations of Filaria rhytipleurites, a Parasite of Cockroaches and Rats,” ‘Comptes Rendus,’ July 8, 1878, and ‘Ann. Nat. Hist.,’ Aug., 1878.—Idem, “Note sur l’anat. et les migrations de deux Nématoides parasites, le Pæcilogaster blatticola et Fil. rhytipl.,” Paris, 1876 (quoted by O. von Linstow).—Giard, M. A., “On the parasitic Isopoda of the genus Entoniscus (infesting Crustacea),” from ‘Comptes Rendus,’ Aug., 1878, in ‘Ann. Nat. Hist.,’ Otc., 1878.—Idem, “On the Orthonectida, parasitic on Echinodermata and Turbellaria (Rhopalura),” ‘Ann. Nat. Hist.,’ Feb., 1878.—Grube, A., “On Cyclops as a new Cestoid-bearing Host,” from ‘Zoologisch. Anzeiger,’ Bd. i, s. 74, in ‘Journ. Royal Microsc. Soc.,’ Nov., 1878, p. 254.—Hunter, J., “Filaria of the Bee,” in ‘Catal. (by Owen) of the contents of the Mus. Royal Coll. Surg.,’ part iv, fasc. i, p. 37, 1830.—Kynston, “Worms attached to a Grasshopper,” ‘Proc. Ashm. Soc.,’ in ‘Corbyn’s India Review,’ and in ‘Journ. of Foreign Sci.,’ 1837, p. 172.—Lima, J. F. da S., “Remarks on the Filaria medinensis or Guinea-worm; on the occurrence of this parasite in the Province of Bahia; and on its entrance into the human body by drinking water;” trans. from the Portuguese by Dr J. L. Paterson, and pub. in the ‘Veterinarian’ for Feb., 1879 et seq.—Linstow, “Helminthologische Beobachtungen,” in ‘Archiv für Naturgeschichte,’ 1876.—Lubbock, Sir J., “On Sphærularia bombi,” ‘Nat. Hist. Rev.,’ 1861.—Idem, “Notes,” &c., ibid., 1864, p. 265.—Mason, J. W., “Note on the Geographical Distribution of the Temnocephala chilensis (parasitic upon a freshwater crayfish, Paranephrops setosus, in New Zealand),” ‘Annals Nat. Hist.,’ 1875, p. 336.—Marion, A. F., ‘Revision des Nématodes (&c.),’ Marseilles.—Maund, B., “A description of Filaria forficulæ,” ‘Rep. Proc. Linn. Soc.,’ in ‘Zool. Journ.,’ 1832–34, p. 263.—Meissner (see Thomson).—Owen, R. (see Hunter).—Pagenstecher (see Bibl. No. 58).—Panceri, P. (e di E. D. Claparède), “Nota sopra une alciopide parassito dell Cydippe densa,” ‘Mem. della Soc. Ital. di Sci. Nat.,’ 1867.—Sars, “Intestinal Worm in an Acaleph.,” from ‘Wiegmann’s Archiv,’ in ‘Ann. Nat. Hist.,’ 1845.—Siebold, C. J. von, in ‘Wiegmann’s Arch.,’ 1835.—Idem, in ‘Ray Soc. Rep.’ (by Busk), 1847.—Idem, “Worms,” &c., ibid., p. 503, 1847.—Idem, “Report on Helminthology, and on the Nemertinæ” (trans. by W. B. Macdonald, in ‘Ray Soc. Rep. on Zool.,’ 1842, p. 280), Edinburgh, 1845.—Idem (see Thomson).—Thomson, A. (for review of the writings of Meissner, Von Siebold, and others, respecting the development of Mermis, Gordius, &c., see the classical and elaborate art. “Ovum”), in ‘Supp. to Todd’s Cyclop.,’ 1859.—Vogt, C., “On some Inhabitants (Cercariæ) of the Fresh-water Mussels,” from ‘Ann. des Sci. Nat.,’ in ‘Ann. Nat. Hist.,’ 1850.—Whitman, C. O., “The Embryology of Clepsine (with valuable Bibliography),” ‘Quart. Journ. Micr. Sci.,’ July, 1878.

Appendix.—The memoirs announced by Dr T. R. Lewis in the January issue of the ‘Microscopical Journal,’ and referred to at the close of my account of Filaria Bancrofti, having appeared, I fulfil the promise previously made (p. 202). In the few lines at my disposal I may observe that the beautiful brochure (quoted below) supplies fuller details of the results already announced by Lewis in the ‘Proceedings of the Asiatic Society of Bengal.’ In respect of the nematoid hæmatozoa, the memoir is chiefly important as confirming Manson’s observations regarding the changes undergone by the Filariæ that have been transferred to the stomach of the mosquito, and especially also, as advancing some novel facts in reference to the occurrence of bird’s blood-corpuscles, associated with embryonic nematoids, in the same viscus of the insect. The worms are regarded by Lewis as transferred avian hæmatozoa, a view which gains strength by their comparison with the similar larvæ which he had detected in the blood of Indian crows (Corvus splendens). In Egypt, as Sonsino had himself informed me by letter, similar hæmatozoa are to be found in crows, and avian filariæ of this kind were long previously described, as Lewis and Sonsino point out, by Borell, Herbert, Schmidt, and Virchow. Facts of this order undoubtedly complicate matters, and suggest that extreme measure of caution in drawing conclusions, which Lewis himself everywhere displays.

Respecting the final changes undergone by the mosquito-filariæ before their re-entrance into the human body, Lewis does not appear to have gone further than Dr Manson. By rupturing the body of the most advanced larvæ, Lewis readily recognised the œsophagus and intestine, but he remarks, significantly, “I have not been able to distinguish any other differentiated viscus in any of the specimens, and certainly, nothing suggestive of differentiation of sex” (p. 83). In an earlier part of the memoir Dr Lewis takes objection to my view that the urinary nematoids found by me in a case of Bilharzia are genetically related to Filaria sanguinis hominis. His distinguished coadjutor, Dr D. Cunningham, also denies the possibility of such relationship. No doubt, if the urinary maternal worm was really oviparous my view is untenable; but the proved presence of imperfectly formed ovarian ova, in which no trace of embryonic formation was discernible, has forced upon me the conviction that prolapsus and rupture of the uterine tubes of the parent worm had occurred, and that their rupture had occasioned the escape of ova in various stages of growth. As free embryos were also detected, the adult worm was probably viviparous. There is an error in the representation of the oval-shaped ovum given in the figure (p. 183). I retain drawings of eighteen perfect nematoid ova from the Bilharzia case, and not one of these shows any double contour of the chorional envelope. In the case of the imperfect ova, the double contour is obviously due to the close apposition of the yelk-membrane to the shell-membrane, there being no true shell. As regards “a correction” which Lewis makes in respect of the question of priority of description of the mature Filaria sanguinis hominis I can only find space to state frankly, that Lewis is perfectly correct. The error was quite unintentional on my part. The adult worm was first discovered by Bancroft, and upon the strength of his admittedly scanty record I named the worm Filaria Bancrofti. In the matter of supplying a proper diagnosis and an anatomical description I was completely anticipated by Lewis. No doubt, Dr Bancroft could have furnished a fuller description of the parasite, had he desired to do so, but here is what he says in the letter addressed to me from Melbourne on the 20th of April, 1877:—“I thought it better to send you this account of filariæ than to publish it direct, as you so kindly set me on the track of the investigation.” Here I feel constrained to remark that few, if any, of my many correspondents in helminthology, have displayed more engaging candour. Whilst actually writing this Appendix (April 15th, 1879) I have received a new record of filarious cases from Dr Bancroft, who also sends me some mosquitoes captured by a victimised patient whose blood swarmed with filariæ. In one of the captured insects Bancroft himself detected forty-five filariæ. The cases have been forwarded to the ‘Lancet’ for publication. Lastly, in reference to the closing paragraph of Bancroft’s previous letter to me (pub. in the ‘Lancet,’ Feb. 1st), I have received the following interesting commentary at the hands of Dr Silva Araujo, whose letter is dated from Bahia, March 3rd, 1879:—“Je dois vous communiquer que ce fait vient confirmer l’idée qui existe chez nous, où le peuple croit et affirme que—quand une personne qui souffrait auparavant d’erysipèle a un abcès cela la préserve de nouveaux accès. La raison ne sera-t-elle pas que dans ce cas, avec l’ouverture de l’abcès, le ver sort? Je le crois. Ces faits viennent démontrer que la cause de la maladie est le ver. Cependant nous avons ici à Bahia plusieurs confrères qui ne le croient point! Et à Rio-de-Janeiro aussi il y en a, peut-être davantage(!).” I will only add that Dr Araujo deceives himself if he imagines that the full etiological significance of parasites in relation to disease will receive general professional recognition for many years to come.

Supplement to Bibliography No. 23, p. 202 (with emendations).—Araujo, ‘Memoria sobre a Filariose ou a molestia produsida por uma nova especie de parasita cutaneo,’ Bahia, 1875.—Idem, “Da filariose,” ‘Globo,’ Jornal do Rio de Janeiro, 1876, e ‘Revista Medica do Rio de Janeiro,’ 1876, anno 3o, No. 2, 15 de Julho, p. 107.—Idem, “Caso de chyluria, elephancia do escrôto, escrôto lymphatico, craw-craw e erysipela em um mesmo individuo; descobrimento da Wuchereria filaria na lympha do escrôto. Tratamento pela electricidade com excellentes resultados,” ‘Gaz. Med. da Bahia,’ 2a serie, vol. 2o, No. 11, Nov. de 1876.—Idem, “A Filaria Wuchereri no sangue,” ‘Gaz. Med. da Bahia,’ Mar. de 1878, p. 106, e seguintes.—Idem, “A muriçoca e as filarias Wuchereri,” ‘Gaz. Med. da Bahia,’ Setembro de 1878.—Idem, “La Fil. immitis,” &c., Transl. of Mem. (l. c., Bibl., No. 45) in ‘Lyon Médical,’ Nov., 1878, p. 319 et 363.—Bancroft, “Instance of a European having taken leprosy in Queensland,” in a letter to myself; see “Case from Bancroft,” quoted at p. 203.—Chassaniol, A. (et F. Guyot), “Hématurie graisseuse ou chyleuse,” in their “Notes de Géographie Méd. recueillies à Taïti,” in ‘Archives de Méd. Navale,’ Jan., 1878, p. 65.—Cobbold, “Worms in the Heart of Dogs,” letter in the ‘Lancet,’ April 5, 1879, p. 498.—Coles, “On Lymph-scrotum,” ‘Brit. Med. Journ.,’ March 9, 1878.—Fayrer, Sir J., “Lecture on Elephantiasis Arabum,” in the ‘Lancet,’ March 29, 1879, p. 433.—Idem, ‘Report of Pathol. Soc.,’ ‘Lancet,’ Feb. 22, 1879, p. 267.—Idem, ‘Rep. of Epidemiological Soc.,’ ibid., p. 269.—Idem, ‘Letter on Filaria;’ see Hoysted.—Ghaleb, O. (with P. Pouquier), “On Filaria hæmatica,” from ‘Comptes Rendus,’ Feb. 5, 1877, in ‘Annals Nat. Hist.,’ April, 1877.—Hoysted, J., “Notes of a Case of Filaria sanguinis in a Dog;” see Bibliog. No. 49, p. 311.—Lewis, T. R., ‘The Microscopic Organisms found in the Blood of Man and Animals, and their relation to Disease,’ Calcutta, 1879.—Idem, “The Hæmatozoa of Man (excerpt of the above),” ‘Quart. Journ. of Microsc. Sci.,’ April, p. 245 (both from ‘14th Ann. Rep. of the San. Commissioner with the Govt. of India’).—Makuna, ‘Letter respecting Fil. sang. hom. in Chyluria’ (l. c., Bibliog. No. 23).

INDEX.