ON ARCTOCEBUS CALABARENSIS 597 
only marking on the exterior of the digit being that produced by the 
projection of the end of the metacarpal bone. 
The proximal phalanx of the index finger is o'15 inch long; the 
distal rather less than o'r inch. 
Thus far the differences between my specimen and that described 
by Dr. Smith are of no moment; but on passing to the dentition I 
find, with a complete general correspondence, a solitary discrepancy 
which I cannot account for. 
Dr. Smith says of the upper incisors :—“ Two together (in pairs), 
with intermediate edentulous space; first incisor the smallest; the 
second nearly twice as large as the first.” 
In the specimen under description, on the other hand, the upper 
incisors are strictly equal in size; and the proportions of the two 
Fic. 2. 
A. The left hand: The digits artificially extended as far as they will go. 
B. The left foot in its natural position, seen from without. 
C. The same, seen from below. 
teeth noted by Dr. Smith are the more remarkable, as they do not 
obtain in any other Lemurs. When, as in Nycticebus and Zarsius, the 
upper incisors are unequal, it is the outer which is the smaller. 
In the face of the resemblances of size, proportion, pelage, and 
sex between the two specimens of Angwantibo, it is difficult to 
admit that this singular difference can have more significance than 
an individual variation. However this may be, the characters of the 
teeth of the Angwdntibo are so well shown in the present specimen 
