﻿EXTERNAL ANATOMY. WALKING FEET. 129 



standing their differences in other respects, possess the 

 common character of having the hinder toe elevated 

 above the plane, or level, of the others ; so that its in- 

 sertion is above the heel of the foot, and not, as in the 

 Raptores and Insessores, directly upon it. As it will 

 be necessary, in the sequel, to notice the feet of these 

 aberrant orders more parti cularly, we confine our- 

 selves in the following observations to that structure 

 which especially belongs to the Insessorial, or perching 

 birds, in all of which the three anterior toes, and the 

 one posterior, are placed upon the same level. These 

 we shall term insessorial feet, and we shall now describe 

 the numerous variations which they present, according 

 to the peculiar habits and economy of the very great 

 number of genera composing the Insessores, or perch- 

 ing order. This structure of foot is either formed more 

 especially, 1. for walking ; 2. for perching ; 3. for 

 clinging ; 4. for climbing ; 5. or are sindactyle feet. 

 We shall then notice the different sorts of scansorial 

 feet, wherein the toes are disposed as above mentioned, 

 which will render unnecessary any observations on the 

 impossibility, or the inexpediency, of giving definite 

 names to the minor variations. 



(117.) Walking feet, among the perchers, do not 

 imply a similarity of structure to those of the Rasores, 

 which never have the hind toe upon a level with the 

 others ; but rather that feet, so formed, are adapted both 

 for walking and perching. Thus every one knows that 

 the crows and starlings walk more frequently than 

 they hop ; and it is therefore essential to birds of such 

 habits, whose chief food is upon the ground, that their 

 feet should have a particular conformation. Hence we 

 find that nearly all terrestrial birds, strictly so called, 

 have the lateral toes perfectly equal, that is, of the 

 same length. The crow (fig. 67. a), rook, starling, 

 and blackbird, besides many others, familiar inhabit- 

 ants of our fields and lanes, sufficiently illustrate this 

 fact. In proportion as the habits of a bird are arboreal 

 rather than terrestrial, so is this equality of the lateral 



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