Agassiz on the Relations between Animals, &c. 369 
* 
Art. XXXVII.—The Natural Relations between Animals and 
© the Elements in which they live; by L. Acasstz. 
*Amone the early attempts to arrange animals in a systematic 
order, we find almost universally, that the natural elements in 
which their different tribes live are introduced as the fundamen- 
tal principle of their classification. During the sixteenth and 
stances in which they dwell, had been introduced into our systems, 
we still find a prevailing influence of such considerations upon 
the circumstances of the natural subdivisions of animals. As 
soon however as the study of comparative anatomy had shed its 
brilliant light upon this question, those views were entirely aban- 
doned, and the whole animal kingdom was finally arranged ac- 
cording to its internal structure. The introduction of this prin- 
ciple was hailed as a new era in the history of our science; and, 
after Cuvier had applied it to a general revision of the whole an- 
mal kingdom, it was and has been universally acknowledged as 
the only safe foundation of a natural classification of animals. 
The recent progress in zoology, and of the various branches of 
natural history connected with it, has however opened the pros- 
pect of further improvements, even upon the basis on which our 
classification at present rests. For embryology is already display- 
ing its vast influence upon zoological questions, and the time is 
not far distant, when its share in the natural arrangement of ani- 
mals will be as large as that of comparative anatomy itself, and 
hen information derived from. all possible quarters shall have 
ma. 
and functions of all animals. For though it is plain that the mere 
‘Stconp Serres, Vol. IX, No. 27.—May, 1850. 47 
