XVII THE POTTO AND ANGWANTIBO 547 
“is not a happy one, for it is continually seeing ghosts; and that 
is why it hides its face in its hands!” 
The genus Perodicticus contains two quite recognisable species, 
known respectively as the Angwantibo and Bosman’s Potto. The 
former has been regarded as referable to a distinct genus, Arcto- 
cebus. A curious internal character of the Potto which is visible, 
or at least can be felt, externally, is the long neural processes of 
the cervical vertebrae, which project beyond the level of the skin. 
The index finger is rudimentary and so is the tail, being only 
just visible (about an inch in length) in the Potto. The colour 
of both genera is a reddish grey, redder in the Potto. The 
incisors are equal and minute. Both species are confined in 
their range to West Africa, and are arboreal like the other 
members of the sub-family. The Potto seems to share the 
leisurely mode of progression of its Asiatic relatives, if Bosman, 
its original describer, is to be trusted. He says: “ By the negroes 
called Potto, but known to us by the name of Sluggard, doubtless 
from its lazy, sluggish nature; a whole day being little enough 
for it to advance ten steps forward.” The same writer did not 
at all appreciate his addition to zoological knowledge, for he 
remarked that the Potto “hath nothing very particular but his 
odious ugliness.” The Angwantibo is rare and but little known. 
Our knowledge of its anatomy is derived from a paper by 
Huxley.’ It is an animal measuring about 103 inches in total 
leneth to the end of the tail, which is only a quarter of an inch 
long. The hands and feet are smaller than those of Perodicticus. 
The index finger is rudimentary and has but two phalanges, and 
it has no trace of a nail. In this it agrees with the Potto, but 
“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.” The dental formula 
of this genus as of the last is I 2 C 1 Pm3 M3. The last lower 
molar has a fifth cusp, which is wanting in the Potto. The last 
upper molar is tricuspid. It is bicuspid in the Potto. It seems 
impossible to avoid agreeing with Professor Huxley that the 
Angwantibo is entitled to generic separation. » 
The genus Loris also contains but a single species, LZ. gracilis, 
and is, as its name denotes, an animal of more slender build than 
the Slow Loris. Its eyes are very large, and the limbs excessively 
1 “On the Angwantibo,” Proc. Zool. Soc. 1864, p. 314. 
