THE FAUNA OF 



SOUTH AFRICA. 



AYES. 



Order II. PICARLE. 



THE order Picariae contains a number of well-marked families, 

 most of them separable by clearly-defined characters, whereas it 

 is almost impossible at present to give a clear and definite diagnosis 

 of the order itself. 



The members of this order agree with those of the Passeres t in 

 that the young are hatched naked and helpless, and do not usually 

 pass through a downy stage, and in that the toes are not webbed to 

 any extent and are all placed on the same level. On the other hand, 

 they differ from the Passeres in having a desmognathous palate 

 (except the Woodpeckers and Swifts), and in having the deep 

 plantar tendons connected by a vinculum. 



The following drawings are given to illustrate some of the more 

 important anatomical characters used in separating the orders and 

 families of birds, most of which are due to the genius of Nitsch, 

 Huxley and Garrod. 



I. The Pterylosis or arrangement of feathers on the hind neck 

 and back. This, as a rule, consists of a median row of feathers 

 separated by two parallel bare tracts running on either side. This 

 arrangement holds good in the case of all Picarians, except the 

 Hornbills. When this line of feathers is defined on the neck it 

 may be forked on the upper back or on the lower back, or not 

 forked at all (fig. 1, p. 2). 



II. The variations in the arrangement of the deep plantar 

 tendons in the tarso- metatarsus were first noticed by Garrod ; we 

 may distinguish six modifications of these. 



(a) Passerine, in which the flexor perforans digitorum splits 

 into three to supply the second, third and fourth toes, while the 

 flexor longus hallucis supplies the hallux only, and is quite free 

 from the other tendon (fig. 2a, p. 2.) 



1 VOL. in. 



