216 



STRUCTUEE AND CLASSIFICATION OF BIRDS 



there is no patagialis longus. The brevis receives rather 

 low down a very strong slip from the pectoral ; near to its 

 insertion it gives off a wristward slip, which is attached to a 

 special tendon arising from the lower end of the humerus. 

 The main tendon passes over this, not attached to it, to the 

 ulnar side. The absent longus is represented only by a 

 thinnish tendon arising from the pectoralis. 



The same structures are found in B. malaharicus, B. 



coronatus, B. bicornis, and in 

 Tocous. In jB. atratus there 

 is in addition an excessively 

 smsll patagialis longus muscle, 

 arising with brevis and con- 

 sisting indeed of but very few 

 fibres. In Bucorvus, on the 

 other hand (fig. 100), the tensor 

 patagii longus is well developed. 

 Each tendon has a slip from* 

 pectoralis {a and a' in fig. 100), 

 but that which joins brevis 

 receives a tendinous slip from 

 the biceps. This, however, as 

 it is not figured by FuEBRiNaBE, 

 is possibly individual. 



Quite exceptionally — among 

 anomalogonatous birds — many 

 hornbills have a broad humeral 

 attachment of the anconmus. 

 The muscle itself arises from 

 the scapula by a Y-shaped 

 {Bucorvus, Buceros) or flat, non-divided (Aceros) head. The 

 humeral ' ankerung ' is found in B. subcylindricus, B. bicor- 

 nis, not in B. elatus, B. malabaricus, B. atratus, Bucorvus 

 abyssinicus, Aceros, or Toccus. The deltoid has no scapular 

 slip. 



The leg formula oi all hornbills is AXY— . 

 The glutcBus maximus is quite absent ; the glutmus ex- 

 ■ternus is only present as a ligament. 



Fig. 100. — Patagial Muscles of 

 Bucorvus (aftee Beddakd). 



//, humerus ; Bi, biceps ; Us, biceps slips (?) ; 

 6.r, t.Pf tensor patagii brevis tendon ; a, a', 

 slips from pectoralis. 



