328 
ME. ST. GEOEG-E MIVAET ON THE SKELETON OE THE PEIMATES. 
it varies between this and a tenth, except in Cercopithecus, Semnopithecus, Ateles, and 
Colobus, being in the last genus less than one-twentieth. 
Its length, compared with that of the entire manus, is greatest in Arctocebus, and then 
in Chrysothrix, in both of which it considerably exceeds one-half. It does so slightly 
in Man, Hapale, and also in Loris. In the rest it varies between this proportion and 
two-fifths, except in the Simiinee *, Cheiromys, and Semnopithecus, and finally, in Co- 
lobus and Ateles, in which two last genera it is less than one-fifth. 
The pollex, when extended beside the index, exceeds it greatly in Arctocebus and 
Perodicticus f . It reaches nearly to the distal end of the second phalanx in Loris, and 
to the distal end (or very near it) of the proximal phalanx in the Cebidae, and mostly 
in Hapale. It reaches considerably beyond the middle of that phalanx in Man, Tarsius, 
and Cheiromys, beyond the middle in Indris, and to its middle in Lemur and Galago. 
Occasionally in the lowest Simiidse it nearly reaches the middle of the proximal 
phalanx, but generally does not extend so far. It goes but very little beyond the 
proximal end of that phalanx in the Gorilla and Hylobates, and still less beyond it in 
Semnopithecus. In the Chimpanzee it barely attains the distal end of the metacarpal 
of the index, while in Simia it decidedly falls short of its end. In Ateles, i. e. in the 
specimens examined (without a phalanx), it reaches more than halfway down the me- 
tacarpal of the index, but in Colobus (with a phalanx) it does not attain its middle. 
The pollex, when compared with the longest digit of the manus, is at its maximum of 
relative length in Cheiromys (in spite of the great length of its longest digit), being 
almost quite three-fourths the length of that digit. Arctocebus and Hapale, Loris, and 
Man follow, its proportion in all four being more than three-fifths. The rest vary be- 
tween this and Hylobates (where it is sometimes only as 33-4 to 100), except Colobus 
and Ateles, in which the proportion is only one-fifth or even less. 
The index , compared with the spine, is longest in Hylobates and Tarsius, where it 
approaches one-half the length of the latter. Then in Simia, Cheiromys, and Ateles, 
where it is considerably more than one-third. In the rest it varies between this and a 
fifth, except in Cercopithecus, the Cebidse below Mycetes, Lemur, Galago, and the 
Nycticebinse, being least in Perodicticus and Arctocebus, where it scarcely exceeds one- 
twentieth. 
The longest digit , whether third or fourth, compared with the length of the spine, is 
greatest in Tarsius, Cheiromys, and sometimes Hylobates, where it exceeds one-half. 
The rest vary between this and one-fifth, except Cercopithecus, Chrysothrix, Lemur, 
Loris, and Arctocebus, being least in the last-mentioned, where the proportion is as 
about 16 to 100. 
* Dr. Lttcae found the pollex with its metacarpal to exceed that of Man in Macacus gelada, that of the 
Orang to he less than that of the Chimpanzee, and that of Hylobates to be greater than that of any other of 
the Simiinse (loc. tit. pp. 307 & 317). 
f In Perodicticus the pollex reaches somewhat beyond the middle of the proximal phalanx of the third 
digit ; in Arctocebus it attains the ultimate phalanx of the third digit. 
