1S2 THE VOYAGE OF H.M.S. CHALLENGER. 



view is not different from the above. Murie does not notice it in the text or the drawings 

 of Otaria and Trichechus. From the position of this muscle, reaching from the spinal column 

 over the "luteal muscle to the outer side of the knee, it must act as a flexor of the thigh and a 

 rotator outwards of the thigh and leg. 



The Sartorius in Phoca vitulina is an elongated slip. It arises from the ventral anterior spine 

 of the ilium, descends backwards, forwards, and slightly inwards, lying to the inner side of the 

 tensor fasciae femoris. It is inserted into the upper edge of the patella. In Phoca hispicla it arises 

 also from a small part of the lower lip of the iliac crest, and is inserted as in Phoca vitulina, but 

 the fibres are also attached to the inner edge of the patella, into the ventral edge of the ligamentum 

 patella?, a few fibres descending along the inner side of the ligament to the head of the tibia. In 

 Phoca barbata it has the same relations as in Phoca vitulina. 



In Macrorhinus Iconinus it arises from the lower edge of the ventral anterior spine of the ilium, 

 which is a continuation of the outer lip of its crest, and from half an inch of the outer lip of the 

 ilium. Its course is as in Phoca vitulina, but it is adherent to the rectus above the patella, and 

 is joined on the dorsal edge by the tensor fascia? femoris. The tendon is broad, and is inserted into 

 the outer edge, and into the outer two-thirds of the superior edge of the patella. The tendon 

 unites with that of the rectus and goes with it to the tibia. 



In Arctoccphalus gazella there was a second sartorius, much smaller than the proper one and 

 posterior to it. The proper or anterior arises from the ventral anterior spine of the ilium, and 

 from the ventral border behind the ventral anterior spine for a slight distance ; it passes downwards 

 and outwards, and is inserted into the inner edge of the patella, sending a fascial expansion to the 

 fascia over the internal condyle to the head of the tibia. The posterior muscle arises from the 

 middle of the venter of the ilium by a slender tendinous slip, descends to the knee, and is inserted 

 over the internal border of the fascial expansion of the anterior one. Lucae only recognises part of 

 the external oblique as its analogue. It appears in Murie's drawings of Otaria and Trichcchus but 

 not in the descriptions. It flexes the thigh, and may slightly adduct and evert it. 



A very noticeable fact is the uncertainty as to the precise insertion of this muscle, its tendency to 

 variation, and the fixity of the origin. Some may be in favour of regarding the tensor vagina? 

 femoris and the sartorius in the Thocina? as offshoots from the external oblique, but the dissections 

 appear to me to indicate that they are distinct from it. I look upon the external oblique as a 

 progressive muscle, increasing in size and carried backwards in adaptation to the crawling movement 

 of the Seals along the ground. In Arctoccphalus where there is no crawling the external oblique 

 follows the ilium and pubes. In the Phocina? it is supplied by the anterior crural nerve. 



The Pectus femoris in Phoca vitulina is a single-headed muscle, and arises from the ventral 

 fourth of the anterior border of the outer surface of the ilium, from the outer surface between 

 the anterior ventral spine and the origin of the gluteus minimus on the outer side, which is about 

 the ventral half of the outer surface, and from below the capsule of the hip-joint, anterior to the 

 middle of the acetabulum. Tims it springs from the outer surface of the ilium, from a surface 

 bounded anteriorly by the anterior border of the ilium, posteriorly by the capsule of the hip-joint, 

 where it is attached to the ilium on the dorsal side by the origin of the gluteus minimus, and on 

 the ventral side by the ventral posterior spine of the ilium. The fibres form a rectangular band, 

 which is partly behind the sartorius and the tensor fascia? femoris. After passing downwards, 

 forwards, and slightly outwards, it is inserted into the upper edge of the patella, and is united with 



