XIII 



PHYLUM CHORDATA 



519 



The scapula is largo 

 and oval in shape : the 

 spine is near the an- 

 terior margin : the 

 post-scapular fossa has 

 ridges for the origin 

 of the muscular fibres : 

 the spine has a well 

 developed acromion. 

 The coracoid process 

 is elongated and in 

 some cases bifurcated. 

 The clavicle is long. 

 The pro-coracoid is re- 

 presented by a separ- 

 ate ossification ; there 

 are rudiments of the 

 sternal end of the 

 coracoid between the 

 clavicle and the first 

 rib. The humerus, 

 radius and ulna are 

 all elongated. The 

 ulna is reduced, and 

 is sometimes only 

 represented by the 

 proximal end, anky- 

 losed with the radius. 

 A large sesamoid is 

 developed in the ten- 

 don of the triceps 

 muscle near the ole- 

 cranon process of the 

 ulna, In the carpus 

 the scaphoid and lunar 

 are united : some- 

 times also the cunei- 

 form is united with 

 these : the pisiform 

 is small. There is 

 no centrale. The un- 

 gual phalanges are 

 absent in the nail- 

 less digits. The pelvis 

 is small, the symphysis 

 pubis often imperfect. 

 The fibula is some- 



