The Gluteal and Femoral Muscles in a Marmoset. 191 



outer side. It was inserted into the tendon of psoas magnus, 

 the small trochanter, and the shaft of the femur below. 



It was supplied within the abdomen by several branches 

 of the anterior crural nerve, one of which also supplied psoas 

 magnus. 



The blending together of psoas and iliacus is a common 

 character in the Primates. In some lemurs there is a double 

 origin to iliacus. 



The Nerves. 



There were six lumbar nerves, the upper five of which 

 corresponded to the five lumbar nerves of man, the 6th 

 corresponded to the 1st sacral of man. 



The obturator nerve was formed by roots from the 2nd, 

 3rd, and 4th lumbar nerves, the contribution from the 2nd 

 being very small. It appeared at the inner side of psoas 

 magnus, ran along the margin of the pelvic brim, and passed 

 through the obturator foramen, dividing as it did so into 

 superficial and deep divisions, both of which supplied the 

 obturator externus. The superficial division pierced the 

 upper edge of the obturator externus, and proceeded down- 

 wards in front of the adductor brevis. It supplied the 

 adductores longus, brevis, and gracilis, and ended in the 

 adductor magnus proper. The deep division pierced the 

 obturator on a deeper or more posterior plane, and thereafter 

 lay behind adductor brevis. It supplied adductor brevis, 

 " adductor magnus posticus," and adductor magnus proper. 



There was no cutaneous branch from the obturator nerve. 



The anterior crural nerve had its origin from the 2nd, 3rd, 

 and 4th lumbar nerves behind the obturator. As in the 

 case of the obturator nerve, the fibres from the 2nd lumbar 

 were very few. (The communicating branch from the 2nd 

 lumbar to the 3rd was chiefly used up in the formation of 

 the external cutaneous nerve, and only a few fibres joined 

 the roots of the anterior crural and obturator nerves.) The 

 anterior crural nerve lay deeply hidden between the psoas 

 magnus and the iliacus, and escaped from between them 

 only after its exit from the abdomen. It gave off cutaneous 

 branches as in man, and supplied the psoas and iliacus in the 



