526 Proceedings of the Royal Irish Academy. 
be inserted into the inner side of the tibia along a line going from 
below the sartorius to the inner malleolns, also into the fascia of the 
back of the middle of the leg, and extending outwards to the fascia of 
the outside of the leg overlapping the biceps. The origin was much 
the same in B. tridactylus, but Professor Macalister found the inser- 
tion only into the inner condyle of the tibia, and Professor Humphry 
describes it as dividing into two parts, of which the more external has 
the usual tibial insertion, whilst the other crosses over the back of the 
leg, and is inserted into the outer side of the fibula, and into the fascia 
adjacent to it in connexion with the ischial part of the biceps. 
Biceps femoris (•21) consists in all of two parts, ischial and femoral, 
the former of which has the usual origin from the tuber ischii, and also 
from its ascending ramiis, and from the descending ramus of the pubis; 
the femoral part in our specimen arises from three-fifths of the outside 
of the back of the femur, and is inserted into the lower two-thirds of 
the outside of the fascia of the leg. In B. tridactylus the second 
portion arises from the upper half of the back of the femur on its 
outer side, and is inserted together with the ischial portion into the 
head of the fibula (Professor Macalister), into the back of the fibula, 
and expanding on the back of the leg as far as the heel, uniting with 
the gracilis (Professor Humphry). 
Semitendinosus ('17) and semimembranosus ('14) arise by a com- 
mon fleshy origin (tendon, Professor Macalister) from the tuber ischii, 
and are fused for a short distance, then becoming distinct from one 
another, they run down to their usual tibial insertion. Professor 
Humphry found them separate from one another for the whole distance, 
but otherwise as above described. 
Adductor longus ('07) arises musculo-tendinously from the hori- 
zontal ramus of the pubis under gracilis, and is inserted into the inner 
femoral condyle. Professor Humphry found a double insertion, 
separated by the femoral vessels, the anterior narrow one going above 
the inner condyle, and the posterior broader portion being inserted 
into the hinder and outer aspect of the lower part of the femur. 
Adductor brevis ("07) arises from the anterior border of the tuber 
ischii and is inserted into the middle third of the linea aspera. 
Adductor primus ('14) takes origin from the posterior border 
of the tuber ischii under semimembranosus, and passes forwards 
and inwards to be inserted into the lowest part of the internal 
condyle. 
Kectus femoris (-13) has a single head, the usual insertion, and 
was not surrounded by vastus ('30) which was single and normal. 
Quadriceps extensor cruris was normal in B. tridactylus. There were 
three ligaments in the hip joint in Arctopithecus, as in Professor 
Macalister's specimen, viz. : — capsular, ilio-femoral, and cotyloid, the 
latter being very faint, and pubio-femoral in direction ; as usual there 
was no ligamentum teres. 
Extensor digitorum longus ('14) arises from the heads of the tibia 
and fibula, as well as from the lower extremity of the femur, its 
