THE TLUMAGE. 



241 



Sc 



tened to the thumb- joint (sometimes replaced by a spur) are called 

 the bastard-wing (alula]. All the remiges are covered at their base 

 by shorter feathers, which are arranged in overlapping rows, and are 

 known as coverts (tectrices, fig. 652, T). In certain cases the wings 

 may become so much reduced that the power of flight is almost or 

 quite lost, a condition which is met with in some running and land 

 birds (Dinornithidce, Kiwi and Ostrich), and also in certain water 

 birds (Penguin). 



The great contour-feathers of the tail are called rectrices (Rt), 

 because during flight they are 

 used for altering the direction 

 and for steering. There are, 

 as a rule, twelve (sometimes 

 ten or twenty and more) rec- 

 trices attached to the last 

 caudal vertebra in such a way 

 that they can be moved singly, 

 and unfolded laterally like a 

 fan, as well as be all raised or 

 depressed together. The roots 

 of the tail quills are covered 

 by a number of coverts, which 

 in some cases attain an extra- 

 ordinary size and shape, and 

 constitute an ornament to the 

 Bird (Peacock). When the 

 power of flight is absent the 

 tail loses its significance as a 

 .steering apparatus, and the 

 tail quills are reduced or com- 

 pletely absent. In such cases, 

 however, some of the coverts 

 may attain a considerable size as ornamental feathers. 



The hind limbs, which are principally used in the locomotion of 

 the animal on firm ground present numerous varieties, according to 

 the mode of locomotion of the Bird. In the first place, walking 

 legs, or pedes gradarii, and wading legs, or pedes vadantes, are to be 

 distinguished (fig. 653). The former are much more completely 

 feathered, being covered at least as far as the articulation of the 

 heel ; but they vary considerably, The following varieties may be 

 distinguished (fig. 653) : pedes adhamantes, with four toes directed 



VOL. n. 16 



FIG. 652. Nomenclature of the plumage and 

 regions of Bombycillagarrula(wSiX-wmg)(s\ightly 

 modified after Reichenbach). S, forehead ; Sr, 

 occiput ; Hh, hind-head; Z, lore; W t cheek; 

 N, nape; S, back; -ZT, throat ; Br, breast; Sa, 

 belly; St, vent; B, tail coverts; Et, tail, with 

 tail'quills (rectrices); Hs, primaries ; As, second- 

 aries ; T, coverts (tectrices) ; P, scapulars (para- 

 pterum) ; Al, bastard wing (alula). 



