AKT. 15 ANATOMY OF THE EAEED AND EARLESS SEALS HOWELL 67 



the greater to the lesser. In the animals dissected by Murie and 

 Miller this muscle was essentially the same, with minor variations, 



M. infraspinatus (figs. 7, 9, 20, 21) in the Zalophus probably had not 

 more than one-fifth the strength of the supraspinatus. It arose over 

 the spinal two-thirds of the infraspinoiis space and converged to a 

 slip that passed over the lateral head of the femur to insert upon a 

 slight ridge upon the lateral base of the greater tuberosity. In the 

 Phoca this muscle was even much smaller — to a surprising extent. 

 Origin was from the deep part of the spine and about one-half of 

 the narrow space which constituted the infraspinous part of the 

 scapula. It passed craniad over the acromial notch and inserted upon 

 the capsule of the shoulder joint adjoining the supraspinatus and 

 over the greater tuberosity. 



The ventral part of the cephalohumeral is homologous with a part 

 of the deltoid. The only remaining part of the latter was the deltoid. 



M. deltoiiets (figs. 7, 9, 17, 20, 21). In both my specimens this was 

 relatively very powerful and overlay almost all of the infra- 

 spinous part of the scapula. In the Zalophus it arose by tendi- 

 nous and fleshy fibers from the entire posterior border of the spine 

 of the scapula and by tou,gh aponeurosis from the dorsal border of 

 the infraspinous fossa, although muscle fibers were not found so far 

 dorsad near the spine. Insertion was aponeurotic, chiefly along the 

 lateral border of the deltoid ridge, but a tendinous slip also passed 

 to the ectepicondyle of the humerus, and the distal border passed 

 inseparably into the substance of the supinator longus. In the 

 Phooa origin was only from the caudal border of the spine, with 

 insertion partly tendinous upon the caudal border of the deltoid 

 crest. In Arctocephalus no mention was made of any junction with 

 the supinator longus, but it was stated that a " tendinous slip goes 

 to the fibro-cellular bar lying upon the anterior border of the radius." 

 In Odobenus there was no connection with tl^e supinator longus. 



M. teres minor (fig. 7) in the Zalophus was exceedingly thin but 

 broad at origin, which was from the " teres major fossa," or the pos- 

 terior third of the infraspinous space. It apparently fused with the 

 subscapularis over the axillary border and the insertion was insep- 

 arable. In the Phoca it was as broad distad as, but much thinner 

 than, the infraspinatus. It arose not as in Zalophus but aponeuroti- 

 cally from the distal half of the ridge between the two concavities of 

 the infraspinous space, and was located between the latter muscle and 

 the triceps. Near insertion the fibers joined the tendinous deep belly 

 of the deltoid, and were inseparable. Miller stated that in Phoca 

 vltuUna insertion was upon the greater tuberosity and the capsule of 

 the joint; but he did not find it in Arctocephalus. In Eu/metopia!s 



