MR. ST. GEORGE MIVART ON THE SKELETON OE THE PRIMATES. 
355 
posteriorly by a deeper transverse groove in him than in other forms. It must be 
admitted, however, that the Mandrill approaches Man very nearly in this. 
As to the length of the metatarsals, compared with that of the metacarpals of the same 
individuals, and estimated by a comparison of those of the third digits of the manus and 
pes, the metatarsals are in excess in all Primates except the Simiinse and Cheiromys ; and 
such would also be the case in the last-mentioned genus but for its peculiarly elongated 
middle metacarpal. In Galago, Perodicticus, Arctocebus, and Tarsius the two segments 
are of very nearly the same length. 
The breadth of the metatarsals, as compared with that of the metacarpals of the same 
individual, is always less * in Man and the Simiinse, both absolutely and relatively 
to the length of the bones ; in the latter respect it is also less in all the other genera of 
the order, except, perhaps, some of the Nycticebinse and Tarsius, 
First Metatarsal . — This bone attains its greatest absolute length in the Gorilla, if we 
except gigantic human forms. 
As compared with the spine, this bone is longest in Tarsius, and then in Hylobates and 
Cheiromys, but it is as much as one-tenth the length of the spine in Indris and Ateles ; 
in the rest it is less, and shortest in Hapale, Perodicticus, and Arctocebus, where it is 
little more than one-twentieth. 
It is longer than the first metacarpal in every species except Simia, but in Perodic- 
ticus the excess is exceedingly small. 
The proximal end has always an enlargement, for the tendon of the peroneus longus 
on the index side of its plantar surface. This process becomes extreme in size in the 
Lemuroidea, where it often comes in contact with the tibial side of the second meta- 
tarsal. There is a mere rudiment of this process in some, e. g. Ateles. 
The proximal end also presents an articular surface elongated in the direction of the 
long axis of the corresponding articular surface of the ento-cuneiforme. This surface 
is sometimes slightly concave, as in Man, generally strongly so, as in most other 
forms ; and in the Lemuroidea it is also somewhat convex in a direction at right angles 
to that of the concavity, corresponding to the saddle-shape of the articular surface of 
the ento-cuneiforme in them. 
The long axis of this proximal articular surface of the first metatarsal very rarely 
(only in Man) runs almost vertically from the dorsal towards the plantar margin of 
the proximal end of the bone (Plate XIV. fig. 14). In the Simiinse it runs obliquely 
from the peroneal side downwards and tibiad to the plantar and tibial angle of the 
proximal surface (Plate XIV. fig. 15); in all the lower forms it runs more transversely 
between the dorsal margin, which is turned more or less tibiad, and the peronead turned 
plantar margin of the same proximal surface (Plate XIV. figs. 16—18). 
It is as if the metatarsal of Man had been removed, softened, and then, after being 
turned so that the dorsum looks tibiad as well as upwards, reapplied to the convex ento- 
* Speaking of C. sabaeus, De X'laikville says, “ Les os du metatarse sont surtoutbien plus longs quo ceux du 
metacarpe, un tiers en sus ; ils sont en outre generalement plus greles ” (Jo.c. cit. p. 19). 
MDCCCLXVII. 3 C 
