26 



PROCEEDINGS OF THE NATIONAL MUSEUM 



VOL. 73 



in the scapula. For instance, in Mirounga it is nearly of the form 

 more often encountered in the Otariidae, and the supraspinous sj)ace 

 is several times as extensive as the inf raspinous. 



There is such a large number of muscles attached to the scapula 

 that it is impossible to sort out the different myological stimuli, and 

 but a few broad generalities are practicable. The supraspinatus as- 

 sists in extending the humerus, indicated as being considerably more 

 powerful in Zalophus. The true inf raspinous fossa, which occupies 



PISJFORAA 



ULNAR E 



StAPHOLUNAH 



CARPALE 1 



C^RPALE 2. 



^UNClfORf^ 



CARPALE 3 



Fig. 8. — Left view of the anterior limb bones of Z.^lophus (Z) and Phoca 



HISPIDA (F) IN approximate POSITIONS IN WHICH THEY ABE USUALLY CARRIED IN 

 LIFE 



about half of the infraspinous space, is more extensive in both 

 animals than the size of the muscle warrants, and it is therefore 

 doubtless in course of becoming still smaller. The infraspinatus is 

 a rotator of the femur, with a slight flexor action in some mammals, 

 but its leverage is small. This function has been assumed in the 

 pinnipeds by the deltoid, which is especially remarkable in the 

 otariids, and with much greater efficiency. Although the triceps is 

 so highly specialized in the Pinnipedia this complex has not been 



