158 ELEMENTS OE OBNITHOLOGY. 



axillary feathers, because they are nearest to the arm-pit. They 

 lie close to the body at the inner margin of the under surface of 

 the wing, and are generally longer and firmer than the rest of 

 the under wing-coverts. They correspond below with the 

 humeral coverts above, and may be well seen in the Duck, the 

 Snipe, and the Plover. 



Claws. — In some birds a claw exists at the end of the thumb ; 

 in others one at the end of the thumb and one towards the 

 apex of the pinion or there only. Besides these claws, claw- 

 hke structures termed spurs may be borne, one on the side of 

 the pinion ; and in one bird, the Screamer {Palameded), there 

 are two of them. Such a structure is called a calcar. 



The Legs. — We must now pass to the hind, or posterior, pair 

 of limbs — the legs — -which are called pelvic limbs, or append- 

 ages, because they are attached, as we shall shortly see, to a 

 portion of the skeleton called the " pelvis." 



As has been said, all birds have a pair of legs, and these 

 organs have a general, essential resemblance to our own lower 

 limbs, having three distinct parts : — (1) the part corresponding 

 to our thigh, (2) the part answering to our leg and called the 

 a-us, and (3) parts which correspond with our foot, the straight 

 upper part of which is called in Ornithology the tarsus. 



There is a knee-joint between the thigh and the leg which is 

 like our own joint in its direction and essential particulars. 



There is also a joint between the cms and the tarsus which 

 roughly answers to our own ankle-joint, but (as we shall see 

 when we study the bones) does not entirely or accurately 

 correspond therewith. 



The ioot^pes — (using that term as the equivalent to our 

 foot) includes the straight and sometimes greatly elongated 

 segment of the limb called the " tarsus," and also the toes, or 

 digits, which diverge from the lower end of that segment, 

 though the toes alone are commonly called the " foot." 



The foot, using that term in its wide sense, is of course 

 always a conspicuous part of the limb, while more or less of 

 the leg and all the thigh are concealed by the plumage, or even 

 enclosed within the general envelope of the skin of the trunk. 

 Thus the knee is never externally apparent, and this circum- 

 stance, together with the conspicuous ankle and long upper 

 pare of the foot, give rise to popular misapprehensions about 

 the nature of the lower limbs of birds. 



The thigh is always very thick. The next segment, or true 



