VII.] PRIMATES. 231 



and the so-called Cape mole (Bathyergus), with its allies, having 

 similar subterranean habits. 



Together with the Oriental, the Ethiopian region shews a 

 marked distinction from all others as the sole habitat of the 

 man-like apes (Simiidce). The Ethiopian forms comprise the 

 chimpanzees (Anthropopithecus) and gorilla (Gorilla), both of 

 which are restricted to the equatorial forest-region, where the 

 former ranges as far east as Uganda, although the latter has a 

 more circumscribed distribution. The occurrence of a fossil 

 chimpanzee in the Indian Pliocene affords the most convincing 

 evidence of the derivation of a large part of the Ethiopian fauna 

 from what is now the Oriental region. Among the ordinary 

 monkeys and baboons (Cercopithetida) there are five genera con- 

 fined to this region. Of these, Colobus differs from the Oriental 

 langurs (Semnopithecus] by the absence or rudimentary condition of 

 the thumb, which frequently has lost all trace of a nail. On the 

 other hand, the large genus Cercopithecus^ which is most fully 

 represented in the forest region, is as nearly related to the Oriental 

 Macacus, from which it differs in the less prominent muzzle, and 

 the absence of a projecting heel, or hinder lobe to the last lower 

 molar tooth. This heel is, however, present in the mangabeys, or 

 white-eyelid monkeys (Cercocebus), all of which are exclusively 

 confined to the forest tract. Although the dog-faced baboons 

 (Papio 1 ) have a wider distribution, ranging from the Cape to 

 Arabia, some of the largest and most peculiar forms, such as the 

 mandrill and drill, are confined to West Africa. This genus is one 

 of those common to the Ethiopian region and the Indian Pliocene. 

 The nearly-allied gelada baboons (Theropithecus], of which there 

 are two representatives, are, on the other hand, exclusively north- 

 eastern types, one being confined to Abyssinia. Among the 

 lemuroids, the galagos (Galago*) which, as stated in the last 

 chapter, belong to a sub-family which attains its maximum develop- 

 ment in Madagascar extend right across the equatorial portion of 

 the continent, descending somewhat on the east coast, where they 

 are very numerously represented. The pottos (Perodicticus], which 

 are nearly related to the lorises of the Oriental region, are, how- 



1 Syn. Cynocephahis. * Including Otogale. 



