258 On the Genera of Hapalide. 
As has been stated, Gray split the genus Hapale into a 
number of genera, using the hair-growths or the ears and the 
adjoining parts of the head*. These characters are useful 
for grouping the species ; but if generic value be assigned to 
them, a much higher value must consistently be granted to 
the characters by which the genera admitted in this paper 
are distinguished. 
Table of the Genera. 
a. Hands with long narrow palm and long digits ; digits 
3 and 4 closely tied together by a narrow web 
reaching nearly to distal end of first phalanx; a 
similar but shallower and wider web between digits 
2 and 3; [ears as under 6’; incisors as under a?] .. Leontocebus. 
6. Hands with comparatively broad short palm and 
short digits separated approximately down to plantar 
pad. 
a’, Laminate margin of pinna complete above, but 
‘tapering away below and vanishing compara- 
tively high up on the posterior surface of the 
basal cartilaginous capsule ; [incisors as under a? |. Cidipomidas. 
6’. Laminate margin of pinna widely continuous 
round the cartilaginous capsule, and terminating 
below the antitragus close to the head. 
a’?, Lower incisors normal, shorter and narrower 
than the canines, and separated from them; 
chin broad, receding to a comparatively slight 
CRNCM Dita) otis sting alana tat eV eN oENe em aVE » not ayo aaah Mystax. 
6°. Lower incisors long, forming a subspatulate 
series with the canines, which at most exceed 
by a little the outer incisor in height and thick- 
ness ; chin somewhat compressed and generally 
strongly receding oes scl ceecvlce ven AURA TEs Hapale. 
Note.—During the passage of this paper through the press, 
the opportunity has arisen of examining a specimen of Mystax 
mystax preserved in alcohol. Confirming what has already 
been stated of this species, | may add that the ears resemble 
those of Mystax midas and that the hands and feet are of the 
type seen in Hapale and Gidipomidas. It is interesting to 
note, however, that on the right hand, but not on the left, 
there is a deeper web between the third and fourth digits 
than I have as yet observed in the case of those genera. 
The web, nevertheless, is wider and shallower than in Leonto- 
cebus, although its presence adumbrates the syndactylism 
described in that form. 
* By analogy the two species of Cercocebus—albigena and aterrimus, 
the latter with obsolete, the former with long tufted whiskers—should 
be generically separated. Elliot, I may add, placed these two species in 
a subgenus Lophocebus; but one of the characters justifying this course 
was derived from an immature deformed (probably menagerie) skull. 
