CHAP. XVII.] MAMMALIA. 179 



discovered, which are believed to belong to this sub-order : but 

 they form two distinct families, — Lemuravida? and Limnotheridie. 

 Other remains from the Miocene are believed to be intermediate 

 between these and the Cebidse, — a most interesting and suggestive 

 affinity, if well founded. For the genera of these American 

 Lemuroidea, see vol. i., p. 133. 



General Remarks on the Distrihviion of Primates. 



The most striking fact presented by this order, from our present 

 point of view, is the strict limitation of well-marked families to 

 definite areas. The Cebida? and Hapalidie would alone serve 

 to mark out tropical America as the nucleus of one of the great 

 zoological divisions of the earth. In the Eastern Hemisphere, 

 the corresponding fact is the entire absence of the order from 

 the Australian region, with the exception of one or two outlying 

 forms, whicli liave evidently transgressed the normal limits of 

 their group. The separation of the Ethiopian and Oriental 

 regions is, in this order, mainly indicated by the distribution of 

 the genera, no one of which is common to the two regions. The 

 two highest families, the Simiidae and the SemnopithecidcC, are 

 pretty equally distributed about two equatorial foci, one situated 

 in West Africa, the other in the Malay archipelago, — in Borneo 

 or tlie Peninsula of Malacca ; — while the third family, Cyno- 

 pithecidse, ranges ovei" the whole of botli regions, and somewhat 

 overpasses their limits. Tlie Lemuroid group, on the other 

 hand, offers us one of the most singular phenomena in geo- 

 graphical distriljution. It consists of three families, the species 

 of which are grouped into six sub-families and 13 genera. One 

 of tliese families and two of the sub-families, comprising 7 

 genera, and no less than 30 out of the total of 50 species, are 

 confined to the one island of Madagascar. Of the remainder, 

 3 genera, comprising 15 species, are spread over tropical Africa ; 

 while three other genera with 5 species, inhabit certain restricted 

 portions of India and the Malay islands. These curious facts 

 point unmistakably to the former existence of a large tract of 

 land in what is now the Indian Ocean, connecting Madagascar on 

 the one hand with Ceylon, and with the Malay countries on the 



N 2 



