LETTER XI. A BRIEF REVIEW OF THE MOLLUSCA, TESTACEA, ZOOPHYTE, XI. IT has already been intimated, that one of the great LETTER characteristics of Creation, has been that of multitudinous diversity. This peculiarly appears in the smaller classes of animated nature, and among them, in those other Orders of beings which, besides the Fish and the Cetaceous, Phocine, and Crustaceous Animals, inhabit the sea and other waters. These have received the discriminating denominations of Mollusca, Testacea, Zoophyta, and Infusoria. Most of them are of a miniature size, and the latter, of that diminutiveness to which we give the general name of Animalcules. The greatest part of them inhabit the ocean: but the last kind abound in land waters, and are found in most infusions. They all belong to the division of the invertebrated animals. They have no vertebræ. The MOLLUSCA, are described as 'naked simple animals, not included in a shell, but furnished with limbs.' The Slug, Limax, is placed by Linnæus as the first genus of the class. There are many genera, and of some of these the species are very numerous. The absence of vertebræ has occasioned them to be considered by some as an inferior class of beings. This degradation in the scale of existence is not satisfactory to other Naturalists, who see in their smaller LETTER frames, indications of a careful and complicated construction.1 XI. The Actinia, or Sea Anemone, is a numerous genus of this order. It is viviparous; it has no aperture but the mouth. Feeding on shell-fish and other marine animals, which it draws in with its tentacula, it rejects in a short time the shells and indigestible parts. It is usually fixed to some basis, and assumes various forms. When its tentacula are all extended, it has the appearance of a full-blown flower. Some of its species adhere to rocks,* others to sea-weeds and millepores, others to stones. One kind, Bellis, the Sea Daisy, has a head like the calyx 5 6 1 M. G. Cuvier thinks that the Mollusques in general, and especially the Cephalopodes, have a richer organization; one in which there are more viscera analogous to those of the superior classes, than the other animals without vertebræ. Hence the Mollusca should not be confounded with the Polypi and other Zoophytes, but be placed a degree higher in the scale. But though their organization approaches that of the vertebrated, yet it is not composed in the same manner, nor arranged on the same plan. Bull. Univ. 1830, p. 447. . . . . M. Geoffry St. Hilaire takes the other side of the question against M. Cuvier. Ib. p. 449. 2 Dr. Turton enumerates 36 species of it. The body is oblong, cylindrical, fleshy and contractile. Its mouth is expansile, surrounded with moving cirri. Linn. Syst. v. 4. p. 100. 3 T. Linn. v. 4. p. 100. The Plumera is a beautiful species. On descending in a diving bell to the wreck of the Royal George, which foundered at Portsmouth, its deck was found covered with sea mud, and with numerous groupes of these Sea Anemonies, which with their colors and extended arms made the whole surface resemble a pleasing flower garden. Ib. The Rufa adheres to rocks. The Viridis inhabits near Alexandria, fixed to submarine rocks. It is an inch in diameter, and has several rows of tentacula. The Gemmacea is on the coast of Cornwall, in the fissures of the rocks. T. Linn. 102 & 4. 5 The Undata has this position. The Priapus adheres to shells in the Red Sea. Ib. The Coccinia is fixed to fuci and stones. The Alba, scarce an inch long, is found fixed to stones in the Red Sea. Ib. 8 XI. of a flower. Some appear to like an association with LETTER their fellows. Their sizes vary, from several inches, to the smallness of a pea." The Scylla is a genus, one of whose species lives on the ocean among the floating sea-weed. The Sepia, or Cuttle Fish, has a short head, with large eyes, and a mouth like a parrot's beak. It has eight arms, with numerous suckers." One species was eaten by the ancients, and is liked by the present Italians.12 Another, of a large size, is also a pleasant food.13 In hot climates, some grow to a prodigious magnitude, and are then formidable for their gigantic holders and absorbing power.1 The Medusa, is another singular genus of this 7 T. L. 193. The Dianthus, or Sea Carnation, inhabits the rocky coasts of England, adhering to the under part of rocks. It hangs down like a Yellow Fig. p. 107. The Sociata, near Barbadoes, is fixed to rocks by its smaller end, and is generally found in large groups. T. Linn. 104. The Nodosa, which inhabits the depths of the Greenland Sea, is four inches long. So is the Gigantea, in the Red Sea. But the Pusilla, met with in the Ocean, lat. 57°, is only the size of a large pea. It forms the principal food of Whales. T. L. p. 102, 3. 10 T. Linn. 11 T. Linn. 118. 'The body is fleshy, receiving the breast in a sheath, with a tubular aperture at its base. In most species are two pedunculated testacea.' Ib. 13 The Officinalis species, living in the Ocean. Whales, and Plaice also, take it. The arms are frequently eaten off by the Conger Eel, but are then reproduced. Ib. 119. In 13 The Tunicata. Its large body sometimes weighs 150 lbs. Ib. 120. 14 This is the Octopus of the Mediterranean and Indian seas. the latter it sometimes grows to a large size, the arms becoming nine fathoms long. In these seas the Indians never venture out without a hatchet, to chop off their arms, in case it should attempt to fasten on them, and to draw them into the water. T. Linn. 119. . . . . . This species, when opened, is said to exhibit so strong and splendid a light as perfectly to illuminate a dark room.' Ib. XI. LETTER Mollusca order, with a multitude of species.15 They consist of a tender gelatinous mass of varying figure, furnished with arms or a tentacular process. The larger species, when touched, cause a slight tingling and redness, and are therefore usually called Sea Nettles. They are supposed to form the chief food of the Cetaceous class. Most of them shine with great splendor in the water." This property, of disengaging and emitting light, is one of those mysteries of the luminous fluid, which has not been adequately studied. This most universal agency of nature is as yet very imperfectly known, tho always about us, within us, and acting constantly around us with silent but irresistible power. The Aurita species of the Medusa is frequently found floating in the sea, from two to three inches in diameter, and when the sun shines upon it, a beautiful splendor is reflected from it.18 The 15 Dr. Turton distinguishes 43 species. The body gelatinous, orbicular, and generally flat underneath. The mouth central beneath. p. 121. 16 Mr. Wilderspon, in the Sea of Forth, seems to have been affected by one of these. As swimming, I was suddenly struck, as by an electric shock. I then discovered that I had swam on a gelatinous substance about 3 feet in diameter, which proved to be a fish surrounded by stings. In a moment it enwrapped me, so that every part of my body was stung; and I could only disengage myself by tearing the animal piecemeal from me, at the peril of my hands, which became just as if I had poured vitriol on them. With great difficulty, I swam back toward the shore: but when I reached the machine, I had not strength enough to dress; and was afterwards led home by two persons. A medical friend ordered an application of oil and vinegar. Intense agony, as if stung by thousands of wasps, continued for about hours; and if it had not then terminated, I must have sunk beneath the torture. I felt an internal soreness, and was unable to eat for two days. The inflammation of the throat continued for a fortnight. Several of these creatures are seen on the sands left by the tide, for about a month of the year.' Wilderspon's Early Discipline. 17 T. Linn. 121. 18 Ib. 123. XI. Noctiluca kind wander in large groupes in the LETTER Mediterranean and Atlantic, illuminating the waves, and, if shaken in sea-water, they discharge sparks of light. The size of this genus varies, from twelve inches in diameter, to an eighth part only of that extent.20 19 The ASTERIAS, or Star Fish, or Sea Star, is another abundant genus of the Molluscous animals." They are all inhabitants of the sea, and have the faculty of renewing the part of their body which they may lose by violence. Some of their colours are interesting.22 But the most curious of their species is the Caput Medusa, which appears in most seas, from the beautiful net-work of its construction.23 Peculiarly numerous now, and as peculiarly important for its fossil abundance in our ancient rocks, and therefore for its diffusion in the primitive ages of our globe, is the ECHINUS, or Sea Urchin. All of its class are residents in the sea, and in most seas many are eatables. Their body is roundish, covered with a bony, sutured crust, and generally 19 T. Linn. 123. 20 The Octostyla species is a foot in diameter. The Corona is four inches across. While the Mullicina is but 1 inch in diameter. 127, 8. "They fix to the bottom, by swimming on the back and bending the rays. There are 45 species mentioned of this genus, in the Linnæus many are in the North Seas, p. 133. 22 The Rosia is of a rich rose colour in his body, above, and sometimes inclining to claret. Ib. 133. 23 Its five rays divide into two smaller ones, and each of these into two others. This mode of subdividing is continued to a vast extent, gradually decreasing in size, till at length the ramifications amount to many thousands, forming a beautiful net work. Its colour is sometimes pale or reddish white; sometimes brown.' T. Linn. 135. |