ART. 13 ANATOMY OF THE EARED AND EARLESS SEALS HOWELL 85 



muscle and the pyriformis of the present specimen were inseparable, 

 the two parts being distinguished only by a faint line presumably 

 between them ectomediad. Origin of the two together was from all 

 but the ventral part of the " lateral " surface of the ilium practically 

 to the acetabular border and thence upon the sacrum over the second 

 sacral vertebrae, and upon the ridge extending to the transverse 

 plate of the third sacral. Insertion was almost entirely fleshy upon 

 the flattened part of the greater trochanter. In Evmietopias Murie 

 reported origin as also from the sacrum, presumably the spines. 



M. gluteus minimus (figs. 11, 12, 16) in the Zalophus seemed to be 

 partially divisible, along its dorsal border only, into three slips. It 

 arose from the lateral surface of the cranial half of the ilium and 

 from two-thirds of the vertebral Iwrder, with a few fibers from the 

 A^entral surface of the ilio-sacral ligament. Insertion was strongly 

 upon the greater trochanter. In the Phoca this muscle was entirely 

 covered by the medius. It arose from the ventral fossa and ridge 

 adjoining the " lateral " surface of the ilium. Insertion was some- 

 what tendinous upon the dorso-medial part of the greater trochanter. 



M. gluteus quartus (figs. 11, 12). No slip representing this muscle 

 was mentioned by either Murie or Miller. In my Zalophus, how- 

 ever, it could not be ignored. It was very slender and arose from the 

 ilium craniad of the femoral process and with attachment also to the 

 tendon of the rectus. It passed just superficial to the latter muscle to 

 insert upon the greater trochanter in the angle between the insertions 

 of the glutei medius and minimus. 



M. pyriformis (figs. 12, 16) in the Zalophus was easily separable from 

 the gluteus minimus, caudad of which it lay. It arose from the last 

 two sacral vertebrae beneath the caudal portion of the ilio-sacral 

 ligament, and converged to a tendinous insertion upon the greater 

 trochanter. In the Phoca, as mentioned, this muscle was inseparable 

 from the gluteus medius. In Phoca vitulinu Miller separated it 

 with care. 



After disposing of the gluteal-pyriformis mass, the complex con- 

 sisting of the gemelli, obturator internus and adductor posticus ap- 

 peared in the seal as consisting of a single, strong, well-rounded 

 muscle and much care was necessary in its dissection, partly, of 

 course, because of the extreme tenderness of the fibers. 



M. gemellus superior (figs. 11, 12) lay next caudad to the pyriformis. 

 In the Zalophus it was a much weaker muscle, arising from the 

 superior border of the ischium just caudad of the acetabulum. In- 

 sertion was upon the caudal aspect of the greater trochanter dorsad 

 of the obturator fossa. In the Phoca origin was relatively farther 

 caudad, and its tendon joined the other which, in turn, joined that 

 of the obturator internus inserting into the trochanteric fossa of the 



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