32 INTRODUCTION. 



extremity are three prominences for the articulation of the toes. 

 In most birds there is at the inner and back part a small bone, 

 /*, sometimes anchylosed, to which the hind toe is attached. 



The toes, 1, 2, 3, 4, are never fewer than three, or more than 

 four, unless the spur of the Gallinaceous birds might be con- 

 sidered as the first toe, in the same manner as that on the first 

 digit of the wing has been by some. In very many birds the first 

 or hind toe is wanting, and in others reduced to a rudimentary 

 state. The toes vary extremely in their length and direction. 

 In all birds the outer or fifth toe has five bones, the fourth or 

 middle toe four, the third or inner three, the second or hind 

 toe two, and the first or the spur one. Some birds however 

 have naturally two spurs or even more on the tarsus. The spur, 

 being merely a rudimentary toe, cannot be in the least degree 

 indicative of an analogy between the Gallinaceous Birds and 

 Ruminating Quadrupeds, as Mr. Swainson appears to consider 

 it. The horns of a bull might as well be viewed as hoofs 

 placed on his head for special purposes, and the horny man- 

 dibles of birds as claws appended to the jaws as a substitution 

 for the fingers. 



This superficial inspection of the osseous system of Birds 

 will suffice to render the relations of the external parts intel- 

 ligible, and prevent the student of ornithology from falling into 

 those strange mistakes to which persons are liable whose know- 

 ledge is not more than skin deep. I may be allowed to ad- 

 duce a few examples from " the Natural History and Classifi- 

 cation of Birds, by William Swainson, Esq."' " The leg," 

 he says, " is obviously divided into three parts : 1. the thigh ; 

 2. the shank or tarsus ; and 3. the foot itself, composed of the 

 toes. The thigh is subject to very few variations beyond relative 

 lenofth, and in being more or less clothed with feathers. In 

 aquatic birds it is generally naked before it reaches the knee 

 joint.'' Never, in any aquatic bird, is the thigh naked ; but it 

 is obvious that Mr. Swainson is not aware that birds have a 

 thigh, or that part of which the bone is marked ^ in Plate I. 

 The knee joint, which he considers to be at ^, is at x, as a 

 little reflection might shew any person, and what he calls the 

 thigh is the leg or tibia. Again, '' the humerus " (referring to 



