you can look upon. The shell is beautiful; the body of the animal within the shell is beautiful; and the orange fringe-work, outside of the shell, is highly ornamental. Instead of being sluggish, it swims about with great vigour. Its mode of swimming is the same as that of the scallop. It opens its valves, and, suddenly shutting them, expels the water, so that it is impelled onwards or upwards; and when the impulse thus given is spent, it repeats the operation, and thus moves on by a succession of jumps. When moving through the water in this way, the reddish fringe-work is like the tail of a fiery comet.
LIMA.
The filaments of the fringe are probably useful in catching its prey. They are very easily broken off, and it is able that they seem to live for many hours after they are detached from the body, twisting themselves like so many worms."[18]
Thus we have slightly touched a few of the details of the history of this great division of animated beings; and we discover that they are not less rich in interesting endowments and faculties, in various contrivances and compensations, in singular habits and instincts, than other animals higher in the scale of organization. But it is only when we study the Mollusca as living beings, that we discover these points of varied interest. The mere collection of shells, however curious their forms and brilliant their colours, would impart but a small amount of knowledge when separated from the animals to which they belong. "The shell-collector of former days looked upon his drawers, if they were rich in rare species or varieties, as containing an assemblage of gems; and, indeed, the enormous prices given for fine and scarce shells, joined with the surpassing beauty of the objects themselves, almost justified the view which the possessor took of his cabinet of treasures. They were to him really 'les delices des yeux et de l'esprit;' and the energetic zeal with which he collected, and the sacrifices that he made to procure a fine and perfect Many-ribbed harp, a Gloria maris, or Cedo nulli, among the cones; an Aurora or Orange-cowry, a Voluta aulica, or Voluta Junonia, &c., were only comparable to the extravagances of those visited by the tulip mania when it was at its height. But though they were the delight of his eyes, they were, in nine cases out of ten, little more to the owner of them: they were mere trinkets on which he looked dotingly, without knowing, and scarcely wishing to know, the organization of the animal whose skeleton only was before him."[19]
In these days, however, the examination of the shell is considered by all who possess any claim to science, as subordinate to the history of the entire animal.
Naturalists arrange the Mollusca in six classes, named Cephalopoda, Pteropoda, Gasteropoda, Conchifera, Brachiopoda, and Tunicata. Of these the first three are sometimes distinguished as Encephala, or furnished with a head; the last three as Acephala, being destitute of that organ.
1 ↑ That is, "having dissimilar nerve-knots."
2 ↑ Zool. Journ. iv. 172.
3 ↑ Introduction to Conchology, p. 199.
4 ↑ Introduction to Conchology, p. 173.
5 ↑ Jones's Animal Kingdom, p, 385.
6 ↑ Johnston's Conchology, p. 134.
7 ↑ Annals of Natural History. October, 1852.
8 ↑ Johnston's Intr. to Conch. p. 125.
9 ↑ Philos. Trans. 1835; Part ii.
10 ↑ Phil. Trans, (abridged) xiii. 566.
11 ↑ Holland's Pliny, vol. i, p. 267.
12 ↑ Encyc. Brit. Supp. vol. iv. p. 269.
13 ↑ Introduction to Conchology, p. 11.
14 ↑ Edin. Med. and Surg. Journal, xxix. p. 88.
15 ↑ Test. Brit. Supp. p. 122.
16 ↑ Animal Kingdom, p. 383.
17 ↑ Ann. and Mag. K. H. Oct. 1848.
18 ↑ Excursions to Arran, p. 319.
19 ↑ Penny Cyclop., art. Malacology.
CLASS I. CEPHALOPODA.
(Head-footed Mollusks.)
If we were to take a Poulpe or a Cuttle-fish from some hole or tide-pool in the rocks, and look upon its many flexible arms studded with sucking disks, its sack-like body, its green staring eyes, and its bird-like beak, we should be ready to say that such an animal presents but a slight analogy with the sluggish and almost shapeless creatures familiar to us under the name of shell-fish. And, in truth, the former do possess a higher rank in the scale of animal life, having their senses developed into greater perfection, and forming, indeed, the link by which the latter take hold of the races which, from their elaborate organization, are placed at the summit of the scale—the Vertebrata.
We shall better understand the connexion between the present Class and other Mollusca, by considering, with Cuvier, that "the mantle unites beneath the body, and thus forms a muscular sac which envelopes all the viscera. This body, or trunk, is fleshy and soft, varying in form, being either spherical, elliptical, or cylindrical, and the sides of the mantle are in many of the species extended into fleshy fins. The head protrudes from the muscular sac, and is distinct from the body: it is gifted with all the usual senses, and the eyes, in particular, which are either pedunculated or sessile, are large and well developed. The mouth is anterior and terminal, armed with a pair of horny or calcareous mandibles, which bear a strong resemblance to the bill of a parrot, acting vertically one upon the other. Its situation is the bottom of a subconical cavity, formed by the base of the numerous fleshy tentacular appendages which surround it, and which have been termed arms by some naturalists, and feet by others."
These
