1864.] PROF, HUXLEY ON ARCTOCEBUS CALABARENSIS. 321 
The median incisors are distant from one another about ;);th of 
an inch. The outer incisors are separated from them by less than 
half that space; but are as near the canines as they are to the me- 
dian incisors. The incisors are not more than jth of an inch in 
breadth, and are chisel-shaped, with their outer angles rounded off. 
Fig. 3. 
Right dental series of both jaws of Arctocebus calabarensis. 
A and C, upper; B and D, lower jaw. 
The inner and outer incisors are as nearly as possible equal in size, 
and their crowns are not more than ;);th of an inch long. The 
pointed and curved canines are between ith and }th of an inch long, 
and measure 0:1 inch antero-posteriorly. Their front edges are 
convex, the posterior concave, and both are sharp and cutting. 
There is a rudimentary cingulum on the outer side of the base of 
the canine, both internally and externally, and the inner face of the 
tooth is produced into a vertical ridge. The base of each of the 
premolars measures about 0°1 inch antero-posteriorly ; viewed from 
without (fig. 3, A) each looks like a shorter canine, with the cingu- 
lum much more marked, and so greatly developed backwards as to 
give rise to a “‘talon”’ (heel, or posterior basal process). From within, 
or above (fig. 3, C), the cingulum appears still better developed, in 
accordance with the increased breadth of the base of the tooth. The 
base of the first premolar (1) is not much thicker than that of the 
canine (0°083) ; but in the second (2) it measures 01 inch, and in the 
third (3) 0°13 inch, In this last tooth, therefore, the crown is rather 
wider than it islong. Opposite the end of the ridge on the inner sur- 
face of the principal cusp, which is present in the premolars, as in the 
canine, rises, within the cingulum, a second, minute or rudimentary 
Proc. Zoou. Soc.—1864, No. XXI. 
