INTRODUCTION. Til 



various accessory tufts or plumes in different genera, as 

 crests, ear-tufts, trains, breast plumes, and axillaries, which 

 last are those situated at the base of the v/iiig internally. 

 The leg is composed of what is popularly called the 

 thigh, but which is really the tibia; (and this is either 

 feathered to the knee, tarsus, or bare for a short space 

 above, as in the order Grallatores) ; the tarsus, or shank, 

 the leg popularly ; and the foot. The tarsus is feathered 

 in some birds, such as Eagles, some Owls, Grouse, some 

 Swallows, &c. ; but is bare in most, and is protected by 

 horny scales, of which, anteriorly, there is either one 

 undivided or several scutee; lateral scales are not always 

 present ; and the posterior scales are either entire or 

 variously divided. The foot consists in most cases of 

 three toes in front, and one behind, the hallux. This 

 last, sometimes called the thumb, is not anatomically the 

 representative of that digit, which only appears in a few 

 birds in the shape of a tarsal spur, but is so called 

 because it is antagonistic in its uses to the front toes. 

 It is sometiuies deficient, as in Bustar<ls, Plovers, Bustard- 

 quails, and in others is reduced to a mere rudiment 

 placed above the level of the other toes. The Ostrich has 

 only two toes. The number of articulations of the toes 

 is tw^o in the hallux, three in the inner toe, four in the 

 middle, and five in the outer one. There are a few excep- 

 tions to this, the true Swifts having only two joints in 

 all their toes. 



The upper surface of the toes, acropodia of some, are 

 protected by scales, and are all terminated by horny 

 claw'S of various size and curvature. In some birds, the 

 Swifts, and the Colies perhaps, the hallux is capable of 

 being directed forwards; in others, Caprimulgid^e, it is 

 directed inwards. In the Scansores and some of the 



