﻿EXTERNAL ANATOMY. RASORIAL FEET. 1 53 



of description is desired, repeated personal examination 

 is essentially necessary ; and this, under the above cir- 

 cumstances, cannot be always attained. 



(132.) Feet of the rasorial type, as we have before 

 observed, are remarkable for their size and strength: 

 this holds good in nearly all the rasorial types among 

 the perchers ; but their full development is only met with 

 in the order Rasores itself. The habit of walking, even 

 among the Insessores, is always indicated by a leg whose 

 tarsus is much longer than the hind toe. This is, conse- 

 quently, a universal character in the Rasorial order, to 

 which is added a smallness and elevation of this toe, not 

 to be met with in the perching order. The lateral toes are 

 always of equal length, and they are connected at their 

 base to the middle one by a short web or membrane : now, 

 was this membrane broader than it really is, it would 

 obviously impede the free action of the joints of the toes ; 

 but, by merely extending for a quarter of an inch or so, 

 it gives strength and stability to the walk of the bird. 

 The claws are altogether different from those of the 

 perchers, because they perform different functions : they 

 are very slightly bent, that they may not be injured in 

 walking ; they are robust, because they are employed in 

 scratching the ground, and they are greatly depressed, 

 or rather horizontally flattened, that this function may 

 be more effectually performed. The reader will find all 

 these marks of discrimination in the claws of the par- 

 tridge ( fig. 83. a) when compared with 

 those of the blackbird. The smallness 

 of the hind toe is not a peculiar char- 

 acter of this order, but is common to the 

 two others which form the abberrant 

 circle of the class; namely, the Grallatores and the Nata- 

 tores. But as this member is longer in the perching order, 

 it is necessary that some of the rasorial birds should have 

 it of an intermediate length, that the passage from one to 

 the other should be easy, and preserve the universal law 

 of progressive development. We accordingly find that 

 in the family of the Cracidce, which connects the Inses- 



