190 THE VOYAGE OF H.M.S. CHALLENGER. 



lip, from the sides of the laminae of the 1st, 2nd, and 3rd sacral vertebrae below the dorsal sacro- 

 iliac ligament, and from the ventral surface of the ligament below the 1st and 3rd sacral vertebra?. 

 The anterior fibres pass backwards and outwards, the middle outwards, and the posterior forwards 

 and upwards, just like those of the gluteus maximus, but on a smaller scale. It is inserted into the 

 great trochanter of the femur. The anterior fibres are fixed to the middle of the front border of 

 the great trochanter; from here the fibres are attached obhquely across the trochanter to the 

 junction of the upper surface with the posterior border, where they fix themselves to the upper half 

 of the posterior border of the great trochanter. 



In Macrorhinus leoninus it arises from below the inferior lip of the ilium, and behind the ridge 

 which extends from the ventral anterior spine to the middle of the acetabulum. It is inserted into 

 the outer surface of the great trochanter above the tubercle on the superior side of the posterior 

 border and the middle of the anterior border. 



In A?xtocephalus gazella it arises from the inferior lip of the crest of the ilium, and from the 

 lumbar aponeurosis. The fibres pass backwards, and are inserted into the great trochanter from 

 midway between the anterior border to the posterior inferior corner of it. In the Phocinae and 

 Macrorhinus it tilts the lower end of the femur outwards, rotates the trochanter inwards, and pulls 

 the femur forwards. In Arctocephalus it draws the head of the bone inwards and forwards. 



The Gluteus minimus in Phoca vitidina and Plwca hispida is beneath the medius, and arises from 

 the outer surface of the ilium behind the ridges passing from the ventral anterior spine to the 

 middle of the front of the acetabulum; this surface of origin is concave. It forms a narrow 

 muscular rectangle which can be divided into three slips. It is inserted into the upper inner half 

 of the front border of the great trochanter, and slightly into the surface of the trochanter adjoining. 

 In Phoca barbata the origin is similar, but the insertion is into the outer half as well as into the 

 inner half of the front border of the great trochanter. 



In Macrorhinus leoninus it arises from the concave surface of the ilium behind the medius and 

 dorsal to the ridge. It is inserted into the anterior border of the great trochanter in its upper half. 



In Arctocephalus gazella it arises from the external surface of the ilium dorsad to the feebly 

 marked ridge (already mentioned) and from the venter of the dorsal sacro-iliac ligament ; and is 

 inserted into the upper half of the front border of the great trochanter above the insertion of the 

 gluteus medius. In all the action is to rotate the femur inwards and forwards. 



The Piriformis in the Phocinae cannot be recognised apart from the gluteus medius until the 

 dorsal sacro-iliac ligament is cut and turned aside. It arises from the ventral surface of the dorsal 

 sacro-iliac ligament posterior to the 1st sacral foramen, and from the sides of the ventral surfaces 

 of the 1st, 2nd, and 3rd sacral vertebrae. The fibres converge and are inserted, into the upper third 

 of the back of the great trochanter of the femur. 



In Arctoccphcdus it closely resembles the same part in Phoca, but arises from the 2nd, 3rd, and 

 4th sacral vertebra;. 



The Gemellus superior in Phoca vitidina and in Arctocephalus lies anterior to the tendon of the 

 obturator internus. It arises from the dorsal surface of the ischial liar posterior to the acetabulum. 

 The Gemellus inferior in Phoca vitulina and in Arctocephalus lies posterior to the tendon of the 

 obturator internus. It arises from the internal surface of the ischium below the tuber extending 

 to the origin of the obturator internus interiorly, and the obturator internus tendon anteriorly. For 

 the insertions of the gemelli in Phoca, see the obturator internus. 



