M. Coulteri. Cylindrical, slightly flattened main stem; branches set uniformly and alternately, short at the base, gradually lengthening as far as the center, and from there diminishing to the apex of the stem, giving a leaf-like outline. The same mode of branching and the same outline are repeated in the branches. The ultimate divisions are like forked divisions, and are somewhat incurved. The plant is six to eight inches high, and in color is of many shades of red and pink. It is found in abundance on the Pacific coast at all seasons. (Plate XXXV.)
M. borealis. Branches and branchlets placed on one side of arched main stems; secondary branches curved in opposite direction and bearing branchlets, also divided on one side only; color dark brown. It is found on the northern Pacific coast. (Plate XXXV.) [pg094]
Genus Gloiosiphonia("Viscid tube")
G. capillaris. Frond six to ten inches high, solitary or in tufts; main stem cylindrical, solid above, hollow below; from about an inch above the base densely beset with short, wide-spreading branches arranged evenly and all around the stem; branches again branched in the same way; branches and branchlets attenuated at base and apex; soft, tender, juicy; shrinks much in drying. The species is easily recognized by its delicate gelatinous substance, tapering branchlets, and brilliant red color. It is found in early summer in tide-pools on the New England coast.
Genus Halymenia
H. ligulata. Frond membranaceous, repeatedly and regularly divided in a forking manner; the larger divisions one half of an inch wide and growing very narrow at the top; four to five inches high, spreading in a fan-shape; color rose-red. It is found at Key West.
Genus Grateloupia
G. Cutleria. Frond coarse, flat, variable; either simple, long, and narrow, or short and broad, tapering at both ends, or blunt at the apex, or deeply cleft into many segments; sometimes with leaflets along the edges; height two to three feet; color reddish-brown; in fading, changes to purple and green, and may be variegated. When simple, the plant resembles Iridæa. Found on the northern California coast.
Genus Prionitis
P. lanceolata. Frond narrow, flat, smooth; leathery stems, which branch irregularly and sparingly from the edges; branches bordered with lance-shaped leaflets; color dark brownish-red; plant ten or more inches high, and varies considerably. (Plate XXXV.)
There are other species, among them P. Andersonii (Plate XXXVI.); all are easily distinguished by the lance-shaped leaflets. Common on the Pacific coast.
| PLATE XXXV. | |
|---|---|
| Microcladia Coulteri. | Microcladia Coulteri, magnified. |
| Microcladia borealis. | Prionitis lanceolata. |
Genus Pikea
P. Californica. Divisions of frond thick, narrow, cartilaginous; central axis one eighth of an inch to one inch wide, three to four inches high, thickly set with similar branches irregularly placed; all bordered [pg095] with numerous forward-pointing branchlets, which in turn have spine-like ramuli of various lengths; frond flat, broadly spreading; dark red. It is common at all seasons on the California coast. (Plate XXXVI.)
Genus Halosaccion
H. ramentaceum. Fronds brownish-purple, six to fourteen inches long, coarse and cartilaginous, cylindrical, hollow, compressed, attenuated at the base; more or less covered with simple or forked hollow branches half the size of the main stem. In exposed pools the plants are short and densely branched; in sheltered places they are larger and more delicate in texture. They are common on the northern New England and northern California coasts. (Plate XXXVI.)
Genus Polyides
P. rotundus. Frond three to six inches high, cylindrical, cartilaginous, repeatedly forked, ends obtuse; spore-masses form numerous lighter-colored excrescences on the upper divisions of the frond; dark red. Common from New York northward, in deep pools and washed ashore. (Plate XXXVI.)
Genus Peyssonnelia
P. Dubyi. Frond completely adherent to the rock or stone on which it grows; color dark purple; somewhat calcareous; redder and thicker than next species. It is found at low-water mark or in deep water on the northern New England and northern California coasts.
Genus Petrocelis
P. cruenta. Frond closely adherent, forming dark-purple velvety patches of indefinite outline on rocks and stones. Common north of Cape Cod.
Genus Hildenbrandtia
H. rosea. Forms continuous pink incrustations of considerable extent on stones and rocks at low-water mark. Common everywhere.
The genera of this suborder are characterized by a calcareous or stony incrustation of the fronds, which gives them the appearance of corals. Most of the species are tropical. [pg096]
Genus Corallina("Coral-like")
C. officinalis, common coralline. Frond grows from a disk in tufts more or less dense. The plant is rigid, and seems like jointed, branched coral. The articulations are cylindrical at the base, wedge-shaped and flattened above. Branches emanate from the top of the articulations. The color varies from reddish-purple to gray-green, and is often bleached white when exposed to the sun. Common in tide-pools and on rocks at low-water mark from New York northward. (Plate XXXVII.)
Genus Melobesia
This genus will attract attention, although it cannot be gathered. It is a thin, brittle, scaly substance of indefinite form, which expands horizontally and resembles a lichen. It forms brown and pink crusts on other algæ and on rocks, stones, and shells.
Genus Bangia
B. fusco-purpurea ("brown-purple"). Fine, hair-like, unbranched, dark-purple filaments, one inch to six inches long. It grows in large patches on rocks and woodwork, floating free, but falling into soft, silky, fleece-like masses when left by the tide. Common on northern shores. (Plate XXXVII.)
Genus Porphyra ("Purple dye")
This plant, except in color, is like the green alga Ulva. In color it is purple of various shades. The species are named from variations in the outline of the frond. They are found everywhere, and throughout the year. The plants are edible, being the laver of commerce, eaten principally by the Chinese, who make them into soup.
P. vulgaris. Frond a broad, thin membrane of purple color, three to twelve inches across; margin much waved; sometimes attached at the center, often widely expanded and folded, sometimes deeply lobed. (Plate XXXVII.)
P. laciniata. Differs from P. vulgaris in being divided into narrow segments or into wavy, ribbon-like forms. (Plate XXXVII.)
There are many animals which consist of but one cell. These are called Protozoa, and comprise the Infusoria and other microscopic organisms. The animals next higher in the scale are Metazoa, or multicellular animals, and the first group of this subdivision is Porifera, the sponges, the lowest of the many-celled animals.
For a long time sponges occupied a disputed ground between the animal and vegetable kingdoms. Aristotle was the first to point out that a sponge is not a plant. The assertion was doubted and combated, but at last the animal nature of the sponge was established. Sponges were then believed to be colonies of one-celled animals, but finally it was decided that they were individuals with cells of different kinds that performed functions analogous to those of higher organisms.
The sponge, as commonly seen, is only the skeleton or framework, so to speak, of the living animal. In its natural state it is a very different-looking object. Its entire surface is covered with a thin slimy skin, usually of a dark color, which is perforated with holes corresponding to the apertures of the canals. The organic portion of the sponge is a soft, jelly-like substance composed of three layers—the external (ectoderm), the internal (endoderm), and the middle (mesoderm). The external layer is composed of flat cells. The endoderm has cylindrical cells, each one of which has a flagellate hair. The main mass of the body, the mesoderm or middle layer, is made up of cells having various functions, some being concerned in the formation of framework, some in digestion, and some in reproduction.
The framework is secreted in the mesoderm, and in different [pg102] genera consists respectively of a horny or silicious or calcareous substance, or of the first two of these substances combined. The sponge of commerce has the first kind and is composed entirely of exceedingly fine flexible fibers of a horny substance called spongin. In other species the spongin is intermixed with spicules of silica, or of carbonate of lime, in various shapes. In the sponges, so much valued as curiosities, called "Venus's flower-basket" and "glass-rope sponge," the framework is composed of silicious spicules alone.
The spicules have a great variety of shapes, being rod-like, knobbed, three-pointed, six-pointed, anchor-like, etc., and are a feature in the classification of sponges.
The sponge is traversed throughout by a canal system, consisting of a series of tubes through which water circulates, carrying air and food to the animal. The exterior of the sponge has numerous small pores and a comparatively few large openings. The fine pores are inhalent, taking in and straining the water of its coarser floating material, and then passing it through perforations in their sides into sacs lined with peculiar cylindrical cells having flagellate hairs, each hair having a collar at its base. These cells, called choanocytes, resemble independent animals of the Protozoa, known as flagellate Infusoria or Choanoflagellata. [pg103] They take in and digest food and eject excrement from the area inclosed by the collar. The cilia (hairs) by their constant movement create currents which keep the water in motion. Water, then, is taken through the pores into the first or incurrent canals; thence it is passed into the ciliated chambers, and thence into the excurrent canals, and out through large passages terminating in large openings called oscula, or craters. The canal systems vary. In some species they become quite complex.
Sponges vary greatly in shape, size, color, surface, rigidity, canal systems, and skeleton. They are cake-shaped, tubular, digitate, palmate, cup-shaped, vase-shaped, cone-shaped, spherical, hemispherical, pedunculate, etc., their shapes depending upon whether their growth is uniform or is excessive in a horizontal or in a vertical direction. When they grow evenly in both directions massive uniform shapes arise. If lateral growth predominates, broad, low, and incrusting shapes result. When there is an excess of vertical growth the forms are digitate; [pg104] but if vertical growth is not greatly in excess and is restricted to the marginal part, cup-shaped forms result, and tubular forms when lateral growth is particularly restricted. In some varieties tubular masses coalesce; sometimes flat forms unite in intricate compressed folds. Differences in rapidity of vertical growth make undulations more or less marked, producing lobes and protuberances. Sometimes narrow vertical growth is retarded and horizontal growth predominates, forming various shapes on apparent stems.
Many of the horny sponges are colored, in shades of yellow, brown, red, and violet; some are black.
Sponges are divided into two classes, the Calcarea and Non-Calcarea. The former have calcareous skeletons, which make them hard and rigid; the latter have skeletons of spongin-fiber or of silicious spicules, or of the two combined.
All sponges, with the exception of one family (the Spongillidæ, which live in fresh water), are inhabitants of the sea, and live at various depths. The sponges of commerce belong to the Non-Calcarea and are all confined to the genus Spongia. In this genus the skeleton is more or less flexible, being composed of spongin. They are shallow-water species, are confined to seas where the waters are of comparatively uniform high temperature, and flourish best when protected by reefs and islands.
There are fisheries for sponges in the waters of the West Indies, the Bahamas, on the southern and western coasts of Florida, and in the Mediterranean and Red seas. Those of the Mediterranean surpass in quality the sponges of our coasts.
Five species of commercial sponges are taken from Florida waters. They are graded by the trade in the order of their importance, as the "sheepswool," "yellow," "grass," "velvet," and "glove." The fishing for sponges is done from small boats, two persons manning each boat. One man sculls, while the other, using a water-glass, scans the bottom. The water-glass is a box with a pane of glass on the bottom. If the glass is held below the surface and the face is placed in the box, the observer is enabled to see with some distinctness the bottom at a considerable depth [pg105] in these clear waters. The sponges are dragged up by hooks—a primitive method which restricts the fishing to shallow water, the fishing here being in water not deeper than thirty feet, but usually three to twenty feet. The sponges are "killed" by being exposed on the beach for several days; they are then placed in "crawls," or pens, where they are washed by the action of the waves for about a week; then, if clean, they are dried, assorted, strung on cords, pressed and baled for shipment. The sponge-fisheries are of considerable value, and much attention is being given to the subject of artificial propagation. It is thought that such beds could be subjected to the regulations which govern oyster-beds. Already the planting of sponges has been shown to be practicable. The living sponge is cut to pieces, and the cuttings are placed in favorable localities. Pieces planted in Florida waters attain a marketable size in one year.
Sponges reproduce by eggs formed in the mesoderm. The eggs escape as ciliated spheres and swim about until they find a place on which to attach themselves. As soon as they become fixed they grow with much rapidity into mature individuals.
Some species seem to prefer association with other animals and live as commensals with crabs. The crab Dromia is always concealed under a sponge, which grows upon its back. Spider-crabs are often overgrown with sponges as well as seaweeds. In this case, however, the crab finds and plants the sponge himself. Aplysella violacea overgrows worm-tubes. Many sponges afford shelter to numerous small animals which bore into their bodies for protection, no animal seeming to feed upon the sponge.
Sponges may be found in tide-pools, on the under side of stones, on seaweeds, and so on. A small bright-red incrusting sponge with irregular lobe-like branches is common on the New England coast; a thin yellow incrusting sponge also is found on the under side of stones. Grantia ciliata, a small urn-shaped species, having a large aperture at the summit, is found in tide-pools.
Perhaps the most singular in habit of any sponge is Cliona sulphurea, the boring-sponge, a common species found from Cape Cod to South Carolina and abundant in Long Island Sound. It [pg106] is bright sulphur-yellow in color, grows in irregular masses of considerable size and fine texture, and has low wart-like prominences. It lives on shells spreading over both surfaces, at first forming little burrows, but eventually penetrating the shell in every direction, honeycombing and at last completely destroying it by absorption. Sometimes it settles upon living shells and greatly irritates the animal, which constantly secretes new lime to cover the perforations in its shell.
These sponges are an important factor in the economy of the sea, as they disintegrate dead shells, which would otherwise accumulate in vast quantities.
Genus Grantia
G. ciliata. Small, urn-shaped or oval, with large aperture at the summit, surrounded by a circle of projecting spicules. It is found in tide-pools and on piles of wharves from Rhode Island northward.
Genus Leucosolenia
L. botryoides. Tubular, branched. Occurs in the same places as Grantia ciliata.
Genus Suberites
S. compacta. Elongated, compressed masses, sometimes in several lobes; attached by one edge; texture fine, firm, compact; surface smooth; color bright yellow. It grows on sandy bottoms, and is common in shallow water south of Cape Cod. (Plate XXXVIII.)
Genus Polymastia
P. robusta. When young it forms yellowish-white incrustations over shells and stones; later it grows into long, slender, round, tapering, finger-like projections. Found on the northern New England coasts in deep water.
Genus Cliona
C. sulphurea, the boring-sponge. Irregular massive form of firm texture; surface covered with scattered low wart-like prominences about one eighth of an inch in diameter; bright sulphur-yellow. It destroys, by absorption, vast quantities of dead shells.
| PLATE XXXVIII. | |
|---|---|
| Halichondria panicea. | Suberites compacta. |
| Hircinia campana. | Esperiopsis quatsinoensis (found on the sea-beaches of Alaska). |
| PLATE XXXIX. | ||
|---|---|---|
| Microciona prolifera. | Chalinopsilla arbuscula. | |
| Chalinopsilla imitans. | Euspongia officinalis, var. tuba. | Chalinopsilla oculata. |
Genus Microciona
M. prolifera. When young this species forms bright-red incrustations over shells and stones; later it rises into irregular lobes and tubular prominences. When fully developed it is profusely branched in a forking manner. The branches are more or less flattened, and often are palmate at the ends. It grows in clusters six inches in diameter, of a dark orange-red color. When dry it is grayish-brown, brittle, and bristly. It is found from Cape Cod to South Carolina, and is abundant in Long Island Sound. (Plate XXXIX.)
Genus Tedania
Irregular, uneven, pale-yellow masses spreading over seaweeds; oscula scattered irregularly over the surface; texture close.
Genus Halichondria
H. panicea, crumb-of-bread sponge. It resembles the crumb of bread, and is found cast up on all beaches. (Plate XXXVIII.)
Genus Chalinopsilla
C. oculata, the finger-sponge. Stem stout, more or less flattened, dividing at the upper end into branches which vary in form and thickness, being finger-like or more or less compressed lobes; oscula scattered over the smooth, undulating surface; texture rather hard, but delicate; color, when living, dull orange-red; when the animal matter is removed, white. The species is found in shallow and deep water from New York to Labrador. Common in Massachusetts Bay. (Plate XXXIX.)
C. arbuscula. Profusely branched in a forking manner from close to the base; branches slender; clusters six to eight inches high and about the same in breadth; color buff or gray when living, yellowish-white when free from animal matter; texture finer and more delicate than that of C. oculata. It is found in shallow water from Cape Cod to North Carolina, and is abundant in Long Island Sound. (Plate XXXIX.)
Genus Euspongia
E. officinalis. This is one of the commercial sponges and is known as the "glove-sponge." It is the one of least marketable value, having inferior elasticity and becoming brittle with age; yet a Mediterranean sponge of the same species, variety adriatica, is of the finest quality and greatest value. This singular fact demonstrates that the quality of sponges depends largely upon physical conditions. E. officinalis has an average height of five to six inches. It grows on rocky bottoms in shallow water on the east coast of Florida. This species has a number of varieties of various forms; some are dome-shaped, others tubular, rotund, flabellate, etc. The surface is covered with fine tufts and is generally free from ridges. On the sides are numerous small apertures, [pg108] and one or more large oscula occur on top. The color of the living sponge is black. (Plates XXXIX, XL.)
E. officinalis, variety adriatica. More or less globose; sometimes attached by a broad base, sometimes by a short stem; latter form more or less club-shaped; oscula scattered over upper surface. Found in the West Indies and the Mediterranean. (Plate XL.)
E. officinalis, variety mollissima, the Levant toilet-sponge. Generally cup-shaped; oscula on inner side of cup or on upper flat surface; very soft and elastic.
E. officinalis, variety rotunda. Usually massive; attached by a broad base; sides vertical; oscula large and conspicuous on top, or small in longitudinal rows on the sides. In the young this variety may have a conical form with only one orifice, but later it has several oscula. Its rotundity of form increases with the number of large orifices, but in the adult stages the form varies, some being conical, while others have the top divided into radiating ridges.
E. officinalis, variety dura. Irregular, massive, horizontally expanded, with conical process on upper surface.
Genus Hippospongia
H. equina. Some of the sponges of this species are massive, spherical, and attached by a small base; others are horizontally expanded or cake-shaped; some have a depression in the upper surface and become cup-shaped.
H. equina, variety cerebriformis. Massive, circular, cake-shaped, often depressed in the center, producing a cup-shape, attached by broad base; surface broken up by parallel longitudinal ridges having many tufts. Cup-shaped forms predominate, and have a more or less rough surface. This is one of the species known as grass-sponges.
H. equina, variety meandriformis, the velvet sponge. The surface of this variety has a protruding flattened cushion of fiber which slightly resembles the convolutions of the brain-coral. Sometimes these cushions are extended into long pencils. The oscula are large and ragged on the edges; the shape is irregular. The average size is seven to eight inches in diameter. (Plate XL.)
H. equina, variety elastica (variety agaricina, Hyatt), the yellow sponge. This is the second grade of commercial sponge, corresponding to the Zimocca sponge of the Mediterranean. It is found growing with the "sheepswool" in a depth of two to twenty feet, and is abundant. It is massive and cake-shaped. The whole surface is a network covered with numerous small, fine cones. (Plate XL.)
The variety dura is classed with this species, which it resembles in appearance, though it is harder in texture.
H. canaliculata. Massive, frondose; more or less horizontally expanded; bears finger-like processes of varying development on the upper surface.
H. canaliculata, variety gossypina, the sheepswool sponge. This is the highest grade of the commercial bath-sponge. It is called "sheepswool" because, perhaps, of its irregular shaggy surface. It is covered with tufts, the larger oscula occupying the intervening depressions.
| PLATE XL. | ||
|---|---|---|
| Euspongia officinalis, var. adriatica. | Hippospongia equina, var. meandriformis. | |
| Hippospongia canaliculata, var. gossypina. | Euspongia officinalis. | Hippospongia equina, var. elastica. |
Sometimes these are very numerous, the whole interior being cavernous; again, the structure is more dense, with fewer large openings and more of the small ones between the tufts; again, the depressions are filled up so that the surface has fewer tufts. When living, the color is shining black. This is the best sponge found on the American coast, and although of coarser texture than the best Mediterranean sponges, it is more durable and quite as elastic. (Plate XL.)
H. canaliculata, variety flabellum (Spongia graminea, Hyatt). This is one of the species of sponges of the third commercial grade, which bear the trade-name of "grass-sponge." The shape is cone-like, with either a flat or a funnel-shaped top. The oscula are on the upper surface. The sides are fluted with deep furrows which contain the small incurrent apertures.
Genus Hircinia
H. campana. The normal variety is vase-shaped, but the species varies greatly in form. Some varieties have branches. When living, its color is black. It is found at Key West in four to forty feet depth. (Plate XXXVIII.)
The animals included in the phylum Cœlenterata were once all called zoöphytes, or animal plants, because of their resemblance to vegetable forms. The name Cœlenterata is derived from two Greek words meaning "hollow" and "intestine," and it describes the anatomical structure of each member of the group. They are commonly known as polyps. In the simplest forms the parts which perform the different functions cannot be distinguished one from the other, and even in higher forms there is but little differentiation. Shakspere's description of old age applies to them: "Sans teeth, sans eyes, sans taste, sans everything."
Nevertheless, this very low order of animals has, like the higher orders, such a diversity of form and habit as to require classification. Some of them are stationary, and of these some branch like plants; some move about by the aid of tentacles, some move by means of vibrating cilia, and others move by the contraction and expansion of the soft body.
Cuvier included them in his Radiata, a class comprising all the animals whose parts diverge or radiate from a central axis. Recent classification has divided the radiate animals into several classes. This arrangement of parts is obviously quite different from that of bilateral symmetry, or the disposal of parts on each side of a longitudinal axis. The type of radiate structure is shown in polyps. The body is a sac, in the center of which is another sac or axis. This is the digestive cavity. Vertical partitions extend from the central to the outer sac, forming distinct [pg114] divisions or chambers. The number of divisions varies with the different species and also with the age of the animal. Other partitions start from the outer sac, and extend toward the central axis, but do not unite with it. These partitions, called mesenteries, are always in definite multiples, varying in different species, new divisions growing between the first partitions in regular order. On the inner edge of these partitions the eggs of the animal are formed, which, when mature, drop into the chambers and pass through openings into the inner sac, or digestive cavity, and out of the mouth into the water.
The animals are classed according as the eggs are formed on all or on special partitions, those being of the highest order where a limitation and constancy of function is maintained. The upper surface of the body has hollow tentacles, each one of which opens into one of the chambers and extends outward. All parts of the animal communicate, and whatever enters the mouth circulates through the whole structure; and when assimilation is completed the residue returns by the same road and is expelled through the mouth. This structure is common to all polyps; but there are great differences in their texture, some being soft and some horny, while others deposit a calcareous skeleton (corals). Some grow in colonies, like the hydroids and corals, and are stationary, others are free and independent; some have but few, others have many tentacles; and they differ widely in size, form, and color.
Hydroids, sea-anemones, corals, sea-fans, starfishes, and sea-urchins are different examples of the radiate structure. They are not, however, all of them polyps.
The Cœlenterata are divided into four classes:
Cœnosarc ("common flesh"): The fleshy axis, or organized living bond, by which the zoöids are organically united to one another. It consists of three layers: ectoderm, endoderm, and mesoderm.
Ectoderm ("outside skin"): The outside one of the three organized layers of which every hydroid is composed.
Endoderm ("inside skin"): The innermost layer.
Gonangium ("seed-vessel"): The external horny receptacle within which the gonophores are developed.
Gonophore ("seed-bearing"): A generative zoöid.
Hydranth ("water flower"): A nutritive zoöid.
Hydrorhiza ("water-root"): The part of the colony which fixes it to other bodies, like a root.
Hydrosoma ("water-body"): The entire hydroid colony.
Hydrotheca ("water-receptacle"): The cup-like, horny receptacle which protects the hydranth.
Mesoderm ("middle skin"): A layer which lies between the ectoderm and the endoderm.
Nematophore ("thread-bearing"): The name of peculiar bodies developed in certain genera from definite points; characteristic of plumularians.
Perisarc ("around flesh"): The transparent, chitinous shell, or unorganized outer membrane of horny consistency, which covers to a greater or less extent the soft parts of the colony.
Zoöid ("animal form"): One of the animals which form the colony. [pg119]