﻿128 ON THE CLASSIFICATION OP BIRDS. 



rection : by this particular structure the bird could 

 bring the tips of all the four claws to touch each other, 

 when grasping a small round substance, a faculty which 

 no other birds, from the different position of their toes, 

 can possibly possess. The annexed sketch (fig. 66. b) of 

 the foot of the little horned owl, or Scops, will illustrate 

 this singular conformation of foot, which is altogether 

 peculiar to such birds of the rapacious order as prey upon 

 living animals. The vultures, who do not seize their 

 food by their talons, have no occasion for such a foot, 

 and their toes are consequently placed in the ordinary 

 direction. 



CHAP. IV. 



THE SAME SUBJECT CONTINUED. ON THE DIFFERENT MODIFI- 

 CATIONS OF PERCHING, CLIMBING, WADING, AND SWIMMING 

 FEET. THE VOICE AND NESTS OF BIRDS. 



(116.) A perching, or insessorial foot, for the reasons 

 already stated, is pre-eminently typical of this member 

 in the class of birds. Feet of this form are adapted 

 both for walking upon the ground and clinging to 

 branches ; thus uniting the properties both of the 

 grasping and the walking foot, hereafter defined. The 

 three anterior toes are not only directed forwards, but 

 those two of them which are on the sides have no power 

 of being turned in a different direction to the middle toe, 

 and this constitutes their essential difference from the rap- 

 torial structure. Nevertheless, it by no means follows 

 that all birds, having three toes directed completely 

 forward, and one backward, belong to the Perchers. 

 The definition we have already given of the orders of 

 birds (14.) will have informed the student, that the 

 Rasores, the Grallatores, and the Natatores, notwith- 



