596 ON ARCTOCEBUS CALABARENSIS 
Dr. Smith gives :—Arm 2} inches; forearm 2}; hand 14; thigh 
24; leg 21; foot 13. 
The differences obviously lie within the limits of individual 
variation. 
Dr. Smith’s description of the nostrils and of the snout fits the 
present specimen very well; but not so the figure given at page 188 
of his paper, in which the snout is far too blunt, and the nostrils 
have too little curvature. Of the tongue I shall speak fully by and 
by ; in general it agrees with Dr. Smith’s description. 
The spinous processes of the cervical vertebrae do not project in 
the manner described by Van der Hoeven in the Potto, though 
they can be readily felt through the skin. Dr. T. Strethill Wright’s 
figures of the hand and foot of Dr. Smith’s Angwantibo would very 
well represent those of the present specimen ; nor need any modifica- 
tion be made in the description of those parts. I may remark, 
however, that short hairs are developed upon the dorsal surface of 
the distal phalanges, as of the rest. 
The disposition of the hands and feet and of their digits, 
however, calls for some special notice. 
All the digits were strongly flexed. The exertion of a considerable 
force was necessary to extend them; and when that force was 
removed, they at once returned to their flexed attitude. Left to itself, 
the hand assumes the prone position, with the thumb inwards, the 
fingers outwards ; under like conditions, the dorsum of the foot is 
turned as much outwards as upwards, and the fibular edge of the 
metatarsal region downwards (fig. 2, B). 
The distal part of the foot can be so rotated that the dorsal region 
of the metatarsus is turned completely upwards and completely 
outwards; but left to itself, it returns to the position just 
described. 
The sole of the foot is formed behind, as usual, by the tuberosity 
of the calcaneum, and is bare; in front, where the hallucal and 
digital divisions of the foot diverge, there is a callous oval projection 
(fig. 2, C, 2) supported by a large sesamoid bone. The skin is bare 
on this projection ; but between it and the ball of the heel is a narrow 
hairy band. 
Dr. Smith does not mention the circumstance ; but, in the hand of 
the present specimen, the two distal free phalanges of the third 
digit are not parallel with those of the fourth and fifth digits, but 
are directed obliquely inwards (fig. 2, A). 
With Dr. Smith, I find only two phalanges in the index finger (the 
second being very short and slender), and no trace of any nail, the 
