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 Bosnian'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 Bosnian, 

 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. 1 It is an animal measuring about 10^- inches in total 

 length 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 Hoeveu in the Potto, though 

 they can be readily felt through the skin." The dental formula 

 of this genus as of the last is I f C ^ Pm f M if. 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 ZoHs.also contains but a single species, L. 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. SQC. 1864, p. 314. 



