182 Proceedings of the Royal Physical Society. 



semi-tendinosus. The presemi-membranosus part was the 

 deeper of the two. Shortly before insertion the two con- 

 stituents separated, and the two parts were placed one above 

 the other, i.e., nearer the head than the other. The upper 

 part was presemi-membranosus. It was inserted by fleshy 

 fibres into the inner and upper aspects of the internal con- 

 dyle of the femur, and into the internal and popliteal surfaces 

 of the shaft of the femur immediately above the internal 

 condyle. The attachment to the inner surface of the condyle 

 was directly continuous with the femoral attachment of the 

 internal lateral ligament of the knee joint. The lower part 

 — the semi-membranosus proper — was inserted into the upper 

 end of the inner surface of the shaft of the tibia well forward, 

 just falling short of the tibial crest, by a round tendon which 

 passed forwards under cover of the internal lateral ligament 

 of the knee. A few fibres were inserted into the upper end 

 of this ligament. A few tendinous fibres passed outwards 

 under cover of the inner head of gastrocnemius to the 

 posterior ligament of the knee joint. There was no insertion 

 into the fascia of the leg. A partial and artificial separation 

 could be effected right up to the origin. 



The nerve supply was a single branch from the nerve to 

 the hamstrings. This branch did not divide till it had 

 entered the interstice between the two parts of the muscle. 



In none of the Primates of which I have seen descriptions 

 is there so close a connection with the presemi-membranosus. 

 The presemi-membranosus seems to have a more close con- 

 nection with the adductor magnus, so much so that it is not 

 always distinguished as a separate muscle. In lower animals, 

 e.g., Insectivores and Carnivores, it is present, and has an 

 origin in common with semi-membranosus. In some Insec- 

 tivores, many Eodents, and most monkeys, it is distinct from 

 semi-membranosus all the way. It is absent in lemurs 

 (Parsons). In the Hapalidas dissected by Windle it does 

 not appear to have been present, nor in the Hapcde described 

 by Bischoff. In the other Primates described by him it was 

 probably the lowest one of the parts of the adductor magnus. 

 In Cynocephalus anubis (7) it was probably the lowest 

 fasciculus of adductor magnus. In the Anthropoids described 



