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



fenioralis of the text of Lucae, and the ilio-femoralis major and minor of his drawing. It is in part 

 formed by a continuation onwards of some of the fibres of the psoas magnus, and by fibres spring- 

 ing from the posterior ventral spine of the ilium. A number of the superficial fibres of the psoas 

 magnus pass over the spine, and run with a fresh set of fibres which arise from the posterior 

 ventral spine. The fibres from these two sources proceed backwards and outwards, lying to the 

 outer side of the psoas tertius, and are inserted into the lower outer third of the inner border of the 

 femur. 



In Phoca barbata it arises from the posterior half of the posterior ventral spine of the iliuni, 

 from the side of the sacrum, from the sacro-iliac ligament, and from the ventral surface of the 

 ilium along the anterior or upper border to the spine. A few fibres of the psoas magnus run into 

 it, and after receiving them it courses along the ©uter side of the psoas tertius, and unites with it 

 near the supracondyloid ridge on the inner border of the femur. 



The Ilio-femoralis anterior in Phoca hispida arises from the posterior half of the posterior 

 ventral spine of the ilium, from the ventral surface of the sacro-iliac ligament, from the sacrum, 

 and from the ventral surface of the ilium posterior to the spine. It passes to the lower end of the 

 inner border of the femur, and is- inserted into the supracondyloid ridge in front of the psoas tertius, 

 and - is partly blended with it. Lucae had obviously recognised this muscle, and though he names it 

 in his plate ix., he does not describe it in the text. 



The Psoas minor or sccundus in the larger Phoca vitulina, as in the Earless Seals, is the largest 

 muscle of this group. It arises from the ventral surfaces of the 14th and 15th ribs and their 

 rib-joints, from the sides of the 14th and 15th vertebrce, from the ventral surfaces of the bodies of 

 these vertebrae, and from the ventral surfaces of the transverse processes of all the lumbar vertebrae, 

 and is inserted into the pectineal eminence. A similar insertion has been recognised by the 

 authorities already named in the specimens they describe. 



In the small Phoca vitulina, Phoca harbata, Phoca hispid a, in Macrorhinus, and in Arctoccphalus 

 it is much smaller than the psoas major, and is a thin fusiform band, which arises by short tendons 

 from the posterior aspect of the rounded tips of the transverse processes of the 2nd, 3rd, and 4th 

 lumbar vertebras. It crosses inwards ventrally to the psoas magnus and tertius, and is inserted into 

 the pectineal eminence. 



In the large Phoca vitulina the lumbo-femoralis posterior is found on the right side only. 

 After dividing the tertius and turning the two ends aside, a muscular band is exposed, which is the 

 direct continuation of the psoas secundus* This is a flat riband-shaped band of fibres from the 

 psoas secundus passing over the insertion of this muscle into the pectineal eminence, and turning 

 outwards upon the psoas tertius to the lower end of the femur on the inner border into which it is 

 inserted. The secundus of the left side had no such distribution, and all its fibres ended in the 

 pectineal eminence. 



The Psoas tertius in the large Phoca vitulina is the most inferior, and passes beneath the psoas 

 magnus over the pelvic brim to the lower inner border of the femur. It arises under co\er of the 

 magnus from the junction of the ventral surfaces and sides of the two last lumbar vertebras. It 

 lies upon the lumbo-femoralis on the right side and the iliacus on the left, and is inserted into the 

 termination of the femoral ridge on the inner border of the femur at the lower end. 



In the small Phoca vitulina it is a band of muscular fibres 1 inch broad, stretching from the 

 lowest lumbar vertebra to the femur. It arises from the ventral surface of the hinder half of the 



