34 



GENERAL HISTORY OF BIRDS. 



"countless number of little slips" thus formed have, in a goose, been estimated 

 to number at least twelve thousand. 



Delicate pairs of muscles, as well as azygos ones, preside over the move- 

 ments of the lingual apparatus; the trachea; and the eye and ear. Their study 

 is full of interest. Moreover the intrinsic muscles of the head are by no means 

 few in number. The temporal^ and massetei's, by their contraction, close the 

 jaw, and the pterygoids, digastric, and several other pairs are also represented. 



In birds of flight, the three pectoral muscles are enormously developed; 

 the pcctoralis major, when contracting, depresses the humerus powerfully and 

 thus gives the downward stroke to the wing in flight, the upward stroke being 

 effected by the action of the pectoral is secundvs and the pectoralis tertijts. 



The dorsal muscles in the Raven are fully represented, there being some 

 fifteen (15) pairs of them, and among these we find the latissimus dorsi, the 

 trapezius, the rhornhoideus, and others. 



^sji: 



Fif. 3. Outer aspect of muscles of patagium of left wing of a bird. (RhatHphastos 

 cuvieri). After Ganod, slightly reduced. //. /., tensor patagii longus; ip. b., tensor 

 patagii brevis; dt. p., dermo-tensor patagii; e. m. r. /., extensor metacarpiradiali* longus; 

 i., triceps; 6., biceps; S. R., secondary reminges. 



A remarkable group of muscles, the tensor patagii 7nuscles, occur in 

 the triangular patagium of the wing in all birds wherein the wing is well de- 

 veloped. These muscles, through their many describers, have come to play 

 quite an important part in the classification of birds. Their variations, how- 



