INDIVIDUAL VARIATION.--On both sides of one specimen, the femoral notch is absent and the proximal end of the muscle is not notched; the proximal part is entirely fleshy and the anterior border is well defined (fig. 20D). _T. cupido_ INDIVIDUAL VARIATION.--The part attaching anterior to the femoral notch has a fleshy origin in one leg (fig. 20B), but in another, no part attaches anterior to the femoral notch (thus the muscle is not notched). In one leg, the insertional tendon is strongly fused to, and continuous with, the ventral edge of the insertional tendon of M. gluteus profundus. _P. p. jamesi_ INDIVIDUAL VARIATION.--The part attaching anterior to the femoral notch may be mainly or entirely fleshy. In one leg, the part attaching anterior to the femoral notch is entirely separate from, although overlapped by, the main part of the muscle for the entire length of the fleshy belly (fig. 20C); both parts have a common insertional tendon. =_M. Psoas_= (M. iliacus), Figs. 13, 15, 18 _T. pallidicinctus_ GENERAL DESCRIPTION AND RELATIONS.--Small and slender; on medial aspect of proximal end of thigh lateral to proximal end of M. ambiens; ventromedial to M. iliotrochantericus medius; proximal end visible from inside pelvis (medial to inguinal ligament); passes dorsolateral to inguinal ligament. ORIGIN.--The muscle arises fleshily from the ventrolateral edge of the ilium posterior to the femoral notch and ventral (adjacent) to the origin of M. iliotrochantericus medius. INSERTION.--The attachment is tendinous to the medial surface of the femur a short distance proximal to the origin of M. femoritibialis internus. INNERVATION.--The posterior division of the femoral nerve, which spirals completely around M. psoas, gives several twigs into the proximal part. INDIVIDUAL VARIATION.--None of significance. _T. cupido_ INDIVIDUAL VARIATION.--In two legs the insertion is partly fleshy. _P. p. jamesi_ INDIVIDUAL VARIATION.--In one leg the insertion is partly fleshy. The posterior division of the femoral nerve perforates the muscle in one instance. =_M. Flexor Cruris Lateralis_= (M. semitendinosus), Figs. 12, 13, 14, 15, 16, 17 This muscle represents only the main head of the muscle for which Fisher and Goodman (1955) used the same name. Their accessory head of M. flexor cruris lateralis is here termed M. femorocruralis. _T. pallidicinctus_