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OX THE CLASSIFICATION OF BIRDS. 



the assertion would wear every probability of being, in 

 one sense, strictly correct. The ruminating order of 

 quadrupeds (Ungulata) 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 {Scansores) are almost as much re- 

 lated to the gallinaceous birds as these latter are to the 

 ungulated quadrupeds, because the Scansores pass into 

 the Rasores, and the Rasores 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 ; 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 place t, we shall 

 now merely glance at their most prominent features. The 

 Quadrumana are the most perfect of all quadrupeds, as 

 the Conirostres are of all the insessorial birds. The 

 Dent irost res and the Ferce are the most rapacious ; the 

 Fissirostres, although not aquatic (like the Natatores), 

 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, j The ana- 

 logy between the Tenuirostres and the Glires, as being 

 the most aberrant groups in each column, are conse- 

 quently the most remote ; while that of the Scansores 

 and the Ungulata 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 Dentirostres, by most writers, are usually 

 commenced upon, from their obvious resemblance to the 

 falcons ; and having adopted tbis mode upon a former 



* The horse, the camel, &c. are in one ; the ostrich, emu, &c. in the 

 other. 



+ Classification of Quadrupeds. 



