REPORT ON THE SEALS. 189 



across the great trochanter to the middle of its posterior border, and then passes out 

 alone; the outer half of its posterior border, down the outer border of the shaft of the 

 femur, to the lower end of the external supracondyloid ridge. The ventral part is inserted 

 into the under surface of the dorsal part near the outer border of the femur, a few fibres 

 "•amino- the femur. In Phoca hi&pida the gluteal muscle was in a very bad condition. It 

 arises from the 4th sacral and 1st to 4th caudal vertebras, and the insertion is as in Phoca 

 barbata. In Phoca barbata it is smaller than in Phoca vitulina, and has three heads. The 

 anterior head arises from the aponeurosis over the erector spinas, by a band of muscular fibres 

 springing midway between the dorsal posterior spine of the ilium and the 1st sacral vertebra, and 

 from the dorsal sacro-iliac ligament. The second or posterior head arises from the posterior con- 

 tinuation of the same aponeurosis, which is attached to the spine of the 4th sacral vertebra, and 

 the 1st, 2nd, and 3rd caudal vertebras. The third or ventral head consists of a series of fibres 

 springing from the side of the dorsal sacro-iliac ligament, opposite the level of the 4th sacral and 

 1st caudal vertebras, beneath the posterior part. There is a space between the first and second heads 

 and the erector spinas, and the dorsal sacro-iliac ligament is uncovered by the gluteal muscles over 

 the sacrum. The fibres from the first head pass back and out, those of the posterior part pass out 

 and forwards over the great trochanter, and form one muscle by the anterior head joining the 

 posterior. The three heads are inserted into the femur by the ventral or third head joining the 

 under surface of the second, and sending a few fibres directly to the femur ; thus two heads are 

 left, the anterior and posterior, which are disposed like the dorsal head in Phoca vitulina. 



In Macrorhinus leoninus there are three parts. The anterior part arises from the dorsal surface 

 of the dorsal sacro-iliac ligament, and from the inferior lip of the crest of the ilium, and after 

 joining the ventral part is inserted with it into the posterior half of the great trochanter. The 

 ventral part lies beneath the posterior part, and arises from the ventral surface of the dorsal sacro- 

 iliac ligament, and from the anterior surface of the 2nd and 3rd sacral vertebras. It goes to the 

 femur, and is joined, near the great trochanter on the anterior border, by the anterior part. The 

 posterior part arises from the fascia over the 1st to the 3rd sacral spines and the 1st caudal, and 

 from the dorsal surface of the dorsal sacro-iliac ligament. It passes transversely outwards to the 

 femur, and is inserted into the outer border of the femur below the great trochanter and into the 

 external condyle. 



In Arctoccphcdus gazclla there are two heads. The anterior arises from the fascia attached to 

 the spines of the 1st, 2nd, and 3rd sacral vertebras, goes outwards to the femur, and is inserted 

 into the lower three-fourths of the posterior border of the great trochanter. The posterior arises 

 from the fascia attached to the spines of the 1st, 2nd, and 3rd caudal vertebras, and is partly 

 overlapped by the anterior head. The fibres pass transversely outwards, and are inserted into the 

 external border of the femur, into the capsule of the knee-joint, and into the head of the fibula. 



Humphry and Lucae do not refer to the ventral part. In Otaria it has two parts, but there is 

 only one in Trichcchus. In the Phocinas and Macrorhinus the iliac part rotates the femur inwards, 

 tilts the lower end outwards, while the posterior part will rotate the femur outwards and flex the 

 thigh. In Arctoccphalus there are no iliac fibres, and consequently no rotation inwards and 

 forwards. 



The Gluteus medius in the Phocinas is situated below the maximus, and arises from the lower 

 lip of the crest of the ilium, from the external surface of the ilium immediately below the lower 



