346 
ON THE CLASSIFICATION OP BIRDS. 
the assertion would wear every probability of being, in 
one sense, strictly correct. The ruminating order of 
quadrupeds (^U/igulatti^ is not only perfectly analogous 
to the rasorial birds, but it is here that these two classes 
evince the greatest propensity to pass into each other.* 
Now the climbers (Scamores) are almost as much re- 
lated to the gallinaceous birds as these latter are to the 
ungulated quadrupeds, because the Scansores pass into 
the Kmores, and the Rnxores of all birds are those which 
notoriously open the passage to quadrupeds ; and thus a 
scansorial bird actually becomes analogous to a rumin- 
ating quadruped. The analogy, from the necessity of the 
case, must be remote j but, by means of the intervening 
links, it becomes established just as perfectly as if it was 
more immediate. Having already illustrated the rela- 
tions of these two circles, in another placet, we shall 
now merely glance at their most prominent features. The 
Quadrnmana are the most perfect of all quadrupeds, as 
the Conirostres are of all the insessorial birds. The 
Dentirostres and the Feree are the most rapacious ; the 
Fissirostrex, although not aquatic (like the Natatorex), 
have, nevertheless, the weakest and the most imperfect 
feet among the perchers. This is precisely the character 
of the Cetacea among quadrupeds ; while, by comparing 
these two groups through the medium of the Natatores, 
the chain of resemblance is still more perfect. I The ana- 
logy between the Tcnriirosti 'BS and the GUres, as being 
the moH aberrant groups in each column^ are conse- 
quently the most remote ; while that of the Scansores 
and the Ungiilata has already been noticed. 
(287.) Having now sufficiently marked out the cha- 
racters and relations of the insessorial tribes we shall 
proceed to illustrate each of them more fully in succes- 
sion. The De^tiiTOxtreSj by most writers, are usually 
commenced, upon, from their obvious resemblance to the 
falcons ; and having adopted this mode upon a former 
* The horse, the camel, &c. are in one : the ostrich, emu, &c. in the 
other. * 
f Classification of Quadrupeds. 
