Liberia <•- 



thumbless (having only four fingers on the hands), this loss of 

 thumb is evidently not an ancient or well-established feature. 

 Examples of nearly all the species may be met with in the 

 adult stage still showing a minute tubercle tipped with a tiny 

 nail as vestige of the thumb, but in the young the presence 

 of the thumb is most marked. I have seen the young of 

 Colobus rufomitratus, which is the Red Colobus of Eastern 

 Equatorial Africa, in which the thumb was nearly as well 

 developed as in any Cercopithecus. As this Colobus grows up, 

 however, the thumb gradually dwindles in size until it disappears 

 altogether or is reduced to a mere tubercle. 



The Lemurs are represented in Liberia by the Potto 

 (Periodiciicus potto), and by at least one species of Galago 

 {Galago demidoffi). The Potto, together with an allied species 

 from Old Calabar and the Cameroons, the Angwantibo,^ is 

 a very peculiar and specialised development of the lemurs, 

 somewhat analogous to the still more extraordinary Loris of 

 Eastern Asia. The Potto has a short, thicic, stumpy tail, 

 apparently thicker at its abrupt termination. It may be easily 

 distinguished from the much rarer Angwantibo by the greater 

 length of the tail, for in the latter animal the tail is reduced 

 to a mere half-inch stump. 



The thick, soft, woolly fur of the Potto is a warm reddish- 

 grey on all the upper parts of the body ; the throat, inner 

 side of the limbs, and under-parts being an ochre-yellow. The 

 somewhat changing greyish yellow fur on the upper parts is 

 produced by each individual hair being dark grey nearest 

 the skin, bright chestnut-red in the middle, and whitish grey 

 at the tip. The nose, lips, and chin are without hair, and of 

 a pale flesh-colour. The large eyes, with perpendicular siit- 



' There are probably several species of Angwantibo. Tliis last lemur is some- 

 times classed in the separate genus Arctocebus. 



684 



