Cours de 0 Histoire Naturelle des Mammiferes. 421 
these animals, are the analogues of the four ossicles of the ear 
in the mammalia, birds, and reptiles. The results at which 
the author arrives are startling, and at first view improbable ; 
but the reader is captivated by the ingenuity of the reason- 
ing, and the acuteness of the observer; nor is he unwilling 
to follow him even when he goes on to prove that the cha- 
racter which is supposed to separate the vertebral from the 
invertebral animals has nothing in it real and discriminative. 
The link which binds these primary divisions of modern 
arrangements are not the Cephal6poda, as Cuvier’s system 
might indicate, nor the Heteropoda, as Lamarck might have 
but it is formed with the Crustacea, which, according to 
Saint-Hilaire, approximate fishes by many analogous cha- 
racters of great weight. ‘Thus, in both crabs and fish, re- 
spiration is performed by the means of compound branchize 
acting in the same way. ‘The digestive organs, those even of 
generation, and, in general, all the systems essential to the 
preservation of the individual, or to the continuance of the 
species, present the same sort of analogy. But have the Crus- 
tacea an osseous system? Have they a vertebral column ? 
Saint-Hilaire replies in the affirmative; and points out, with 
much ingenuity, the essential sameness and analogies of the 
shell and skeleton. The rings of the shell are compared to 
the rings of the vertebrze of the tortoise in particular; and 
arguments are deduced from this resemblance, from the phe- 
nomena presented in the growth of the vertebree in general, 
and from some particulars ‘of structure observed i in monsters, 
&c., to prove that the external position of the shell, so far 
from presenting any difficulty, is, in fact, in perfect accordance 
with the theory, the shell being analogous to the vertebrae of 
the higher classes in a foetal state. As for the difference in 
their chemical composition, this, it is replied, is only in the 
proportions of the component salts, and not in any difference 
in the nature or quality of them. And, in truth, what “ en 
derniére analyse” is a bone but a salt, eoinposed of phosphate 
of lime in the higher, and of carbonate of lime in the lower 
animals ? 
This doctrine, as we have already mentioned, was first 
published in a consistent and philosophical form by Saint- 
Hilaire, who has many disciples in France, and a greater 
number in Germany; where, indeed, some vain attempts have 
been made to rob him of the merit oe originality, or to share 
that merit with him. The doctrine, however, has likewise its 
opponents, and among them is Cuvier, a host in himself. To 
this prince of naturalists it seems untenable, even when re- 
stricted in its application to the vertebral animals; and he 
