ME. ST. GEORGE MIVART ON THE SKELETON OF THE PRIMATES. 
327 
four outer digits in all the Lemuroidea, except Tarsius. In Arctocebus and Perodic- 
ticus the index is extraordinarily short, consists only of two phalanges, and is abso- 
lutely and relatively the shortest digit of both manus and pes. It is also as short as, 
or shorter than the metacarpal which supports it, which in all other forms it exceeds 
in length. 
As compared with the whole manus, the index is longest in Chrysothrix, Tarsius, La- 
gothrix, Mycetes, Lemur, and sometimes Hylobates, where it exceeds half the length of 
the former. Excluding the Nycticebinse, it only falls below two-fifths in some of the 
lower Simiidse. 
The third digit is absolutely longest in Simia ; as compared with the length of the 
whole manus, it is longest in Tarsius and Chrysothrix, where it exceeds three-fifths the 
length of that segment, and then in Lagothrix and Mycetes. 
It exceeds two-fifths in all, but very slightly so in Arctocebus, in which it is shortest. 
It is the longest digit of the manus in Man and the Simiidse, Nyctipithecus, Chryso- 
thrix, and Tarsius. In the Cebinse the fourth equals it. 
It is never the shortest nor ever the one which projects least distad. It projects 
furthest distad of the digits of the manus in the Anthropoidea, except Pithecia, and 
in Tarsius. 
The fourth digit is the longest one of the manus, and also projects furthest distad in 
Pithecia, and in all the Lemuroidea except Tarsius. 
It about equals the third digit in length in many of the Cebidse and in Hapale. 
It is never the shortest, even excluding the pollex. The fourth digit projects further 
distad than does the index, in Troglodytes, Simia, the Cebinse, and Lemuroidea. The 
projection of the two is about equal in Hylobates and the lower Simiidse. 
The fourth digit is almost always somewhat longer than the second. 
The fifth digit is never the longest or most distally projecting one of the manus. 
It is the shortest one, except the pollex, in Man and the Simiidse, and it is about 
equal to the index in the Cebidse and Tarsius. It projects least of the four outer digits 
in the Anthropoidea and in Tarsius. 
The proportion borne by the longest digit, without its metacarpal, to the longest 
metacarpal, is greatest in Cheiromys and Tarsius, where the first is more than twice 
and a half the length of the second. Then in the Nycticebinse, where it is considerably 
more than twice as long. In the rest it varies between this proportion and once and a 
quarter, except sometimes in Cynocephalus, where the longest digit may scarcely exceed 
the longest metacarpal by more than one-fifth of the length of the latter. 
Digits with their Metacarpals. 
Thus estimated the pollex is absolutely longest in Man, when of average size, and 
then in the Orang and Gorilla. 
Its proportion to the spine is greatest in Tarsius, namely more than one-quarter ; 
then in Cheiromys, and sometimes in Hylobates, where it equals one-fifth. In the rest 
