662 



A HISTORY OF 



OF CRUSTACEOUS AND TESTACEOUS FISHES. 



e 



CHAPTER CL. 



THE DIVISION OF SHELL FISH. 



IN describing the inhabitants of the water, 

 a class of animals occur, that mankind, from 

 the place of their residence, have been con- 

 tent to call fish ; but that naturalists, from 

 their formation, have justly agreed to be un- 

 worthy of the name. Indeed, the affinity 

 many of this kind bear to the insect tribe, 

 may very well plead for the historian who 

 ranks them rather as insects. However, the 

 common language of a country must not be 

 slightly invaded ; the names of things may 

 remain, if the philosopher be careful to give 

 precision to our ideas of them. 



There are two classes of animals, there- 

 fore, inhabiting the water, which commonly 

 receive the name of fishes, entirely different 

 from those we have been describing, and 

 also very distinct from each other. These 

 are divided by naturalists into Crustaceous 

 and Testaceous animals : both, totally unlike 

 fishes to appearance, seem to invert the 

 order of nature; and as those have their 

 bones on the inside, and their muscles hung 

 upon them for the purposes of life and motion, 

 these, on the contrary, have all their bony 

 parts on the outside, and all their muscles 

 within. Not to talk mysteriously all who 

 have seen a lobster or an oyster, perceive 

 that the shell in these bears a strong analogy 

 to the bones of other animals; and that, by 

 these shells, the animal is sustained and de- 

 fended. 



Crustaceous fish, such as the crab and the 

 lobster, have a shell not quite of a stony 

 hardness, but rather resembling a firm crust, 



and in some measure capable of yielding. 

 Testaceous fishes, such as the oyster or 

 cockle, are furnished with a shell of a stony 

 hardness; very brittle, and incapable of 

 yielding. Of the crustaceous kinds are the 

 Lobster, the Crab, and the Tortoise : of the 

 testaceous, that numerous tribe of Oysters, 

 Muscles. Cockles, and Sea-Snails, which offer 

 with infinite variety. 



The Crustaceous tribe seems to hold the 

 middle rank between fishes, properly so call- 

 ed, and those snail-like animals that receive 

 the name of testaceous fishes. Their muscles 

 are strong and firm, as- in the former; their 

 shell is self-produced, as among the latter. 

 They have motion, and hunt for food with 

 great avidity, like the former. They are in- 

 capable of swimming, but creep along the 

 bottom, like the latter: in short, they form 

 the link that unites these two classes, that 

 seem so very opposite in their natures. 



Of testaceous fishes we will speak here- 

 after. As to animals of the Crustaceous kind, 

 they are very numerous, their figure offers 

 an hundred varieties: but as to their nature, 

 they are obviously divided into two very 

 distinct kinds, differing in their habits and 

 their conformation. The chief of one kind 

 is the Lobster; the chief of the other, the 

 Tortoise. Under the Lobster we rank the 

 Prawn, the Craw-Fish, the Shrimp, the Sea- 

 Crab, the Land-Crab, and all their varieties. 

 Under the Sea-Tortoise, the Turtle, the 

 Hawksbill-Turtle, the Land-Tortoise, and 

 their numerous varieties. 



