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ON THE CLASSIFICATION OF BIRDS. 



scales: and it may be remarked, generally, that they 

 are almost obsolete in the perching order. The rasorial 

 birds, on the contrary, possess them in the highest state 

 of development. To ascertain this, let the student 

 examine the leg of a common partridge : the anterior 

 scales of this bird are large and transverse, but divided 

 by an undulating line down the middle of the foot into 

 two series : on each side of the leg are placed the lateral 

 scales, very small, of a lengthened oval shape, and oc- 

 cupying but a narrow strip, although they are arranged 

 in three series : following these are two rows of pos- 

 terior scales, one on each side of the leg, divided in an 

 obliquely transverse direction, and fully as large as those 

 in front. There can be no doubt that a leg, thus 

 strengthened and protected, possesses much more power 

 than if its covering was less perfect, and this will be 

 farther manifested upon examining the legs of the Bra- 

 zilian partridges, forming the genus Crypturus ( fig. 62.): 

 here the anterior scales are thin, with their .divisions 

 finely, and even obscurely marked ; the lateral are almost 

 obsolete, but the posterior, which are arranged trans- 

 versely, are remarkably broad and strong, as if to com- 

 pensate for the weakness of the others. Now, as the 

 legs of this genus are obviously less robust than those 

 of our partridge, although both live equally upon the 

 ground, it would seem to follow that the posterior scales, 

 above all the others, are more especially essential to 

 terrestrial birds, and* that it is for this reason we find 



them more pre- 

 valent and more 

 developed in the 

 Rasores than in 

 any other order. 

 The strong and 

 acute spurs and knots, with which so many of the feet of 

 these birds are armed, are seated in the line of the poste- 

 rior scales, and seem, in fact, but the excessive enlarge- 

 ment of some one or two of them : this singular develope- 

 ment of a spur may be traced in the young bird, when 



