352 
ME. ST. GEOEGE MIYAET ON THE SKELETON OE THE PEIMATES. 
The proximal surface is sometimes convex, as in Macacus, Lemur, and others ; some- 
times, as in Man, it is nearly flat. The tibial surface has generally two facets, at its 
distal end, for the second metatarsal, as in Macacus, Lemur, and others. Sometimes 
there is only one such, as in Troglodytes and Ateles. The peroneal surface has gene- 
rally two facets for the cuboides, as in Macacus, Lemur, Loris, and Troglodytes. In 
Ateles there is only one, which is at its upper anterior angle. In Man there is also 
only one, but it is posterior in position. 
The vertical diameter of its distal articular surface is sometimes in excess, as in Man. 
Sometimes it is the transverse one which is so, as in Lemur and Loris. Sometimes, as 
in Macacus, the posterior inferior angle of the bone is produced into a rounded head, 
though this is not so marked as is that of the meso-cuneiforme. Sometimes, on the 
other hand, the posterior surface slopes rapidly downwards and forwards, as in Lemur 
and Hylobates. 
The bone projects distally in Man considerably more than the cuboides or meso- 
cuneiforme do, and sometimes it does so in Ateles. It projects distally beyond the 
meso-cuneiforme in the Chimpanzee, Hylobates, Semnopithecus, Macacus, the Pithe- 
ciinse, the Nyctipithecinse, Cebus, Plapale, Indris, Lemur, Loris, and Galago. Much so 
in Tarsius, slightly so in Cheiromys. Very slightly or not at all so in the Gorilla, and 
not at all in Simia and Ateles. Sometimes it projects distally beyond the cuboides, 
but not beyond the meso-cuneiforme, as in Lagothrix and Mycetes. 
Cuboides . — The length of the cuboides, as compared with that of the os calcis, is greatest 
in Hylobates, where it sometimes attains one-half. In the rest it varies between this 
and Galago, where it scarcely exceeds a quarter, and is least of all in Tarsius, where it 
is less than one-tenth *. 
The line of junction of this bone with the os calcis is generally anterior to that of 
the astragalus and naviculare. It is exceedingly so, of course, in Tarsius and Galago, 
and it is markedly so in all the Lemuroidea besides, though least so in the Nyctice- 
binse, especially in Perodicticus. It is also decidedly anterior in Nyctipithecus, Chryso- 
thrix, and Pithecia. In other forms it is generally slightly so, except in Lagothrix and 
Mycetes, where the two lines of junction form but one, Ateles, where the junction 
of the naviculare with the astragalus may be anterior, and Man and Troglodytes, where 
the latter condition generally, if not always obtains. 
The distal articular surface is sometimes almost flat or only slightly concave, as in 
Man ; sometimes decidedly concave but concave only, as in Lemur, Loris, and the Cebidse ; 
sometimes concave above and decidedly convex below, as in the lower Simiidae. 
The posterior surface offers an inferior projection (generally rather, or quite on the 
tibial side of the bone), which varies in size with the corresponding concavity of the os 
calcis, being very prominent in Loris and Galago f . 
* Owing, of course, to the abnormal length of the os calcis in Galago and Tarsius. 
t See the. woodcut and description of this joint in Galago Senegalensis, given by Dr. Lucae {Joe. cit. 
p. 314). 
