ME. ST. GEOEGE MIYAET ON THE SKELETON OE THE PEIMATES. 
341 
The pit for the tendon of the popliteus is generally marked, and is deep in Troglo- 
dytes, Simia, Cynocephalus, and Man ; also in Ateles, Mycetes, Cebus, and Hapale. It 
is very deep and large in the Nycticebinse, and appears to attain its relative maximum 
in Nycticebus. 
The depression for the internal lateral ligament seems less marked in Man than in the 
other Anthropoidea.- Of the Lemuroidea I have found it very marked in Perodicticus 
and deep in Lemur. 
The angle formed by the neck of the femur with its shaft varies from about 155° 
(Simia) to 128° (the Gorilla) or 125° (Indris). 
The angle formed by the shaft of the femur with a horizontal surface on which both 
condyles are made to rest, varies from about 103° in Man to about 90° in the Chim- 
panzee. This angle measures the descent of the inner condyle beyond the outer one, 
which is greatest in Man, though very considerable in others, as, e. g., sometimes in 
Cynocephalus, and especially Ateles *. 
Tibia. 
In the whole of the Primates the tibia is an elongated bone, considerably enlarged 
at its proximal end, and less so at its distal extremity. 
Except in the genus Tarsius, it never anchyloses with the fibula. 
There is generally a distinct tubercle giving attachment to the ligament of the pa- 
tella, and the external (peroneal) surface of the bone is almost always more or less ex- 
cavated for the reception of the tibialis anticus muscle. 
The posterior surface of the lower end of the bone has generally two distinct grooves, 
one for the passage of the tendons of the tibialis posticus and flexor longus Mgitorum 
muscles, the other for that of the flexor longus hallucis. 
The tibia has the greatest absolute length in Man, to whom the Gorilla in this respect 
succeeds, but the breadth between the tuberosities is greatest in that Ape, Man being 
only second. 
The length of the tibia (measured to the extremity of the malleolus), compared with 
that of the spine, varies from more than four-fifths, as in Tarsius, to scarcely more than 
three-tenths, as in Perodicticus and Arctocebus. In most, however, it is between two- 
fifths and one-half the length of the spine. 
Its length is generally a little less than that of the femur, but it sometimes slightly 
exceeds it. In Cynocephalus, Troglodytes, and Nycticebus it is decidedly shorter, being 
to the femur in length as less than 85 to 100 ; but only in Man does the proportion fall 
so low as 80-5 to 100. 
The length of the tibia, as compared with that of the humerus, is greatest in Tarsius, 
where it is more than twice as long, and then in Indris and Galago, where it is more 
than, or almost as much as, once and a half as long. In all, the femur’s length ex- 
ceeds that of the humerus, except in Mycetes, Ateles, Lagothrix, and the Simiime, being 
* See the specimen No. 4708 in the Osteological Collection of the Eoyal College of Surgeons. 
3 A 2 
