80 THE GENERAL ANATOMY OF THE LEMUROIDEA [SECT. A 



8. The muscles of the lower limb attract particular notice 

 on account of the modifications induced in their human repre- 

 sentatives owing to the assumption of the erect attitude. 



In the Lemur, the M. gluteus maximus appears definitely as a 

 sheet arising from (a) the posterior superior spine of the ilium, 

 (b) the fascia over the back and lower end of the sacrum, (c) an 

 aponeurosis over the caudal vertebrae, and (d) from the transverse 

 processes of two caudal vertebrae, this (d) being the thickest part. 

 It is inserted into the femoral shaft. Though extensive in origin, 

 the muscle is nevertheless a mere sheet. Anteriorly to it, a second 

 sheet-like muscle arises from the iliac crest as far as the anterior 

 superior spine and is attached close to the M. gluteus maximus on 

 the femur. This may well represent the original form of the 

 human M. tensor fasciae femoris. 



The M. biceps femoris has no "short" or femoral head. It 

 arises (with the M. semitendinosus) from the tuber ischii, and 

 is inserted, not into the fibula, but into the fascia of the leer, 

 some of its fibres being traceable almost as far as the external 

 (fibular) malleolus at the ankle. The M. tenuissimus, repre- 

 sentative (in certain mammals) of the short head of the M. biceps, 

 has not been recognized in the Lemurs 1 . 



The M. adductor " brevis " is longer and larger than the 

 M. adductor " longus." The M. gracilis blends below with the 

 cord-like M. semitendinosus (as in Tarsius, v. infra). 



A curious muscular strip winds spirally round the capsule 

 of the hip-joint. In position, it corresponds to the lower limb 

 of the human ilio-femoral ligamentous baud. 



The chief features of the M. quadriceps extensor cruris are 

 (1) the enormous size of the M. vastus lateralis (which runs up to 

 the trochanter anteriorly as well as laterally;, and (2) the connecting 

 slip between this muscle and the M. rectus femoris. These 

 conditions are encountered again in Tarsius (v. infra). 



Of the muscles below the knee-joint, we may note that the 

 M. tibialis anticus is of very great size, and that the M. tibialis 

 posticus has no tibial attachment (v. infra Platycnemia). In 

 this respect it resembles the M. soleus which likewise contains 

 no tibial fibres, and in this respect, presents the primitive form 

 1 Cf. Klaatsch, Morphologisches Jahrbuch, Band xxix. 1902, p. 263. 



