33 
excrescences, equal in proportion of magnitude, com- 
pared with the body, to those of the rhinoceros, the 
bull, or the deer. f 
The amplitude of covering and external armature 
which is observable, augmented in some to a max- 
imum, diminished in others to a minimum, among 
beasts and birds, is no less remarkable in other 
classes of animals and in the vegetable kingdom. 
The crocodile is coated in mail, with elevated la- 
minz extending down the back in a double line 
united in one line on the upper part of the tail. 
The frog is bare. The backs of the iguana and 
lacerta basiliscus exhibit spinous processes™. Among 
fish some are conspicuous in their scaly covering: 
the salmon, the carp, and the perch afford familiar 
instances. In some the whole body appears bare, 
or only enveloped in slime, the scales not being 
visible without a microscope; as in the murzna and 
eel. Some are remarkable for the glossy smooth- 
ness of their appearance, as the mackarel; some are 
tuberculated and thorny, as the ray; some with 
partial bony plates, as the sturgeon; some rough 
like a rasp, as the shark and dogfish; some covered 
with spines like those of the porcupine, as the sea 
scorpion, the diodon hystrix, ostracion, &c. Of the 
crustacea several crayfish are remarkable for their 
tuberculated, spinous, and hairy covering"; some, 
both of land and water, are clad in smooth and _ po- 
lished mail, as the scorpion and the prawn. 
m The sirens of Carolina and of Carniola are smooth as eels. 
" Cancer araneus, C. hirtus, C. scorpio, C. maia, C, homarus, &c. 
D 
——— 
