TESTACEOUS FISHES. 



680 



element where it resides does not prevent the 

 inhabitant from enlarging. How the soft slime 

 of the snail hardens, at the bottom of the sea, 

 into the stony substance of a shell, is not easy 

 to conceive ! This slime must at least be pos- 

 sessed of very powerful petrifying powers. 



All animals of the snail kind, as was ob- 

 served before, arc hermaphrodites; each con- 

 taining the instruments of generation double. 

 But some of the sea kinds copulate in a dif- 

 ferent manner from those of the garden. The 

 one impregnates the other; but, from the po- 

 sition of the parts, is incapable of being im- 

 pregnated by the same in turn. For this rea- 

 son it is necessary for a third to be admitted 

 as a partner in this operation: so that, while 

 one impregnates that before it, another does 

 the same office by this; which is itself impreg- 

 nated by a fourth. In this manner, Mr. Adan- 

 son has seen vast numbers of sea-snails united 

 together in a chain, impregnating each other. 

 The Bulin and the Corel perform the offices 

 of male and female at the same time. The 

 orifices in these are two, both separate from 

 each other: the opening by which the animal 

 performs the office of the male, being at the 

 origin of the horns; that by which it is pas- 

 sive, as the female, being farther down upon 

 the neck. It may also be observed as a ge- 

 neral rule, that all animals that have this ori- 

 fice, or verge, as some call it, on the right side, 

 have their shells turned from the right to the 

 left ; on the contrary, those which have it on 

 the left side, have their shells turned from left 

 to right, in a contrary direction to the former. 



But this is not the only difference between 

 land and sea-snails. Many of the latter en- 

 tirely want horns; and none of them have 

 above two. Indeed, if the horns of snails be 

 furnished with eyes, and if, as some are wil- 

 ling to think, the length of the horn, like the 

 tube of a telescope, assists vision, these ani- 

 mals that chiefly reside in the gloomy bottom 

 of the deep, can have no great occasion for 

 them. Eyes would be unnecessary to crea- 

 tures whose food is usually concealed in the 

 darkest places; and who, possessed of very 

 little motion, are obliged to grope for what 

 they subsist on. To such, 1 say, eyes would 

 rather be an obstruction than an advantage ; 

 and, perhaps, even those that live upon land 

 are without them. 



Those that have seen the shells of sea- 

 snails, need not be told, that the animal which 

 produces them is larger than those of the 

 same denomination upon land. The sea 

 seems to have the property of enlarging the 

 magnitude of all its inhabitants ; and the same 

 proportion that a trout bears to a shark, is 

 often seen to obtain between a shell bred upon 

 the land, and one bred in tlte ocean. Its con- 

 volutions are more numerous. The garden- 

 snail has but five turns at the most ; in the 

 sea-snail the convolutions are sometimes seen 

 amounting to Ion. 



There is a difference also in the position 

 of the mouth, in the garden and the water- 

 snail. In the former, the mouth is placed 

 crosswise, as in quadrupeds; furnished with 

 jnw-bones, lips, and teeth. In most of (he 

 sea-snails, the mouth is placed longitudinally 

 in the head ; and in some obliquely, or on 

 one side. Others, of the Trochus kind, have 

 no mouth whatsoever; but are furnished with 

 a trunk, very long in some kinds and shorter 

 in others. 



Snails of the Trochus kind, furnished thuo 

 with an instrument of offence, deserve our par 

 ticular attention. The trunk of the Trochu* 

 is fleshy, muscular, supple, and hollow. Its 

 extremity is bordered with a cartilage, and 

 toothed like a saw. The snails that are pro- 

 vided with this, may be considered as the pre- 

 dacious tribe among their fellows of the bot- 

 tom. They are among snails, what the tiger, 

 the eagle, or the shark is among beasts, birds, 

 or fishes. The whole race of shellrd animals 

 avoid their approach; for their hnbitations, 

 however powerfully and strongly built, though 

 never so well fortified, yield to the superior 

 force of these invaders. Though provided 

 with a thick, clumsy shell themselves, yet 

 they move with greater swiftness at the bot- 

 tom than most other shell-fish, and seize their 

 prey with greater facility. No shell so large 

 but they will boldly venture to attack; and, 

 with their piercing augre-like trunk, will 

 quickly bore it through. No efforts the other 

 animal makes can avail : it expands itself, and 

 rises to the surface : but the enemy rises with 

 it : it agaiti sinks to the bottom, but still its 

 destroyer closely adheres. In this manner 

 the carnivorous shell-fish, as some naturalists 

 call it, sticks for several days, nay weeks, to 

 5D* 



