On the Angwantibo of Old Calabar. 175 
character ; at least, this Angwantibo seems to be somewhat 
intermediate in its characters between the first two subdivi- 
sions of the genus Slenops as given by Van der Hoeven, viz. 
— (a) Tail sJiort ; index of hand very short, rese^nbling an 
unarmed tubercle ; and — {b) Tail very short. The Ang- 
wantibo having the index of hand very shorty resembling an 
unarmed tiibercle ; and also, the tail very short. To include 
this animal, the first character of section (a) would require to 
be altered to — tail short , or very short ; index of hand very 
short, &c. It seems to me, indeed, from the discovery of this 
Angwantibo (assuming it to be a new species), that the 
greater or less length of the tail is not sufficiently distinctive 
to allow any characters taken simply from it to be used for 
the division into sections of the comprehensive genus Stenops 
of Van der Hoeven. 
The generic character which Van der Hoeven gives of the 
Genus Stenops — index of hand short, not longer than pollex, 
in the sections (b) and (c), or the equivalent Genera Nyctice- 
bus, Geoff., and Loris, Geoff. — from the examination I have 
been able to make of these animals, appears to be due to the 
smaller relative size of the metacarpal hone, and the phalanges 
of the index finger, luhich are three in number, as in all 
the other fingers (except the thumb). In the Potto, however, 
and this Angiudntibo (as will be afterwards described), which 
fall under his section (a), and the genus Perodiciicus, Benn, 
the character of index of hand very short, resembling an 
unarmed tubercle, is due, not only to the small relative size 
of the bones of that finger, but also to the presence of only 
TWO very small phalanges (the same number as in the thumb), 
the other fingers having three. This anatomical difference 
forms a good distinction or character between section (a), 
the Genus Perodicticus, Benn., and the other Genera, which 
Van der Hoeven has also included in his great Genus 
Stenops. 
The only species noticed by Van der Hoeven under sec- 
tion (a) of his genus Stenops, and, as far as I am aware, 
the only one known, is the Stenops potto or Perodicticus 
Geoffroyi of Bennett, and it, like this Angivdntibo, is a native 
of Africa ; the other described Genera, or species of Van der 
