24 
seek their food chiefly under water, and whose 
breathing is frequently for a long time suspended, 
retain the aperture; as the beaver and sea otter. 
Other peculiarities, connected with the principal 
organs of respiration and circulation, connect toge- 
ther seals and sea otters, porpoises and tortoises, 
and the diving birds; such as a considerable dila- 
tation of the vena cava. Varieties, even partial ex- 
ceptions, exist however in different genera, as in the 
dugong, in which the ventricles of the heart form 
two distinct organs. The foramen ovale was found 
closed in the young animal. Home Phil. Trans.1820°. 
Varieties of structure manifestly adapt all organ- 
ized beings to different conditions of existence: but 
the same mode of adaptation is not always chosen 
to fit all, placed in any definite condition, to such 
state. 
¢ Again and again, in every part of nature this 
> See Carus, Introd. to Comp. Anatomy, translated, with notes, 
by Gore, p. 296, 297. 
© In Dugald Stewart’s “‘ Philosophy of the Active and Moral 
Powers of Man,” vol. ii. book 3. chap. 2. sect. 2. Svo. in a chap- 
ter containing a beautiful and comprehensive survey and refuta- 
tion of the perverse sophistry of the most mis-leading sceptics and 
atheists, the remark in the text is thus anticipated. 
‘«« There are a great, variety of cases, particularly in the animal 
economy, in which we see the same effect produced, in different 
instances, by very different means; and in which, of consequence, 
we have an opportunity of comparing the wisdom of nature with 
the ends she has in view.” ‘Art and means,” says Baxter, (In- 
quiry into the Nature of the Human Soul, vol. i. p. 136, 3d ed.) 
** are designedly multiplied that we might not take it (in the or- 
der of creation) for the effect of chance: and in some cases the 
