344 
MR. ST. GEOKGE MIYAET ON THE SKELETON OE THE PEIMATES. 
No constant characters appear to exist as to the medullary foramina, which are one or 
two in number, near the middle or upper part of the back of the shaft, on the peroneal 
side of the bone. The artery always enters from above downwards. 
The Patella. 
This bone offers few marked or constant noteworthy characters. 
It is generally oval, but is rounder and relatively thicker in the Gorilla than in Man ; 
it is very small and round in the Orang. 
It is longer and narrower in Mycetes than in most other Anthropoidea, but it attains 
its maximum of relative length in Indris, where it tapers downwards, and is so bent that 
the upper and lower halves of its outer (anterior) surface form together 'an angle which 
sometimes approaches 90°. 
It is long also in Lemur and Cheiromys*, but it is small in the Nycticebinse and 
Tarsius. 
Fibula. 
This bone is always distinct from the tibia, except in Tarsius, where its lower half 
anchyloses with the tibia, which thus appears to furnish both the malleoli. 
Its length varies with that of the tibia ; and it is always very much more slender than 
that bone, especially in Man, Ateles, Hylobates, Indris, and Microrhynehus f . 
The fibula is generally nearly straight, but curves slightly in one direction or in an- 
other. In Man it is very decidedly concave forwards, and a similar curvature, though 
less marked, exists in the lower Simiidae, Pithecia, and Loris. I have observed it 
convex forwards in the Orang, Ateles, Mycetes, Indris, Lemur, and Galago, and 
convex outwards in Hylobates, Chrysothrix, In this, and Lemur. But there is, I 
Believe, but little constancy in this character. 
The outer side of the head of the fibula may be convex, flat, or slightly or deeply 
concave, and the articular surface for the tuberosity of the tibia may also be fiat or 
slightly or strongly concave. The head of the fibula is much expanded in the Nyctice- 
binee, and articulates with the tibia by an antero-posteriorly elongated groove. 
The malleolus is generally much produced outwards, and projects about as much as, 
or rather less than, the tibial malleolus, except in Man, in whom alone the external 
(or peroneal) one is much deeper than the internal malleolus. 
The under surface of the malleolus has generally a more or less marked fossa, but the 
presence and size of this are very irregular and inconstant. The malleolus is often 
grooved behind for the tendons of the peronei muscles, especially in Nycticebus. 
The lower articular surface for the tibia varies but slightly in extent. 
The fossae, which more or less excavate the surface of the fibula, and the ridges which 
divide them, are in no Primate developed to such a degree as they generally are in Man. 
Yet Simia, the Gorilla, and Cynocephalus approach him rather nearly in this respect. 
* Owen, Trans. Zool. Soc. vol. v. pi. 19. 
t Proc. Zool. Soc. 1866, p. 165. 
