DISTRIBUTION OF MONKEYS AND LEMURS 225 



which we will take first of the group, remarkable for their 

 slender body and the excessive length of their tails, are 

 distributed over Southern Asia and the adjoining islands 

 of the Malay Archipelago, and are numerous in species, as 

 many as twenty-nine or thirty being of probable validity. 

 Dr. Blanford describes as many as fourteen of them in 

 his " Fauna of British India," as met with within the limits 

 of India, Ceylon, and Burma. Of these, one, S. schistaceus, 

 has mounted high into the Himalayas, where it ascends to 

 an elevation of 10,000 feet and is never met with below 

 5000 feet. But this species is undoubtedly derived from 

 the plains of India, being a very close ally of S. entellus, 

 which has a wide distribution over the northern provinces. 

 Another well-marked species of this genus is found high 

 up in Eastern Tibet and North-western China, where it 

 inhabits the mountain forests and has been named S. 

 roxellawe from its conspicuous turned-up nose. Borneo, 

 Sumatra, and Java, have each of them distinct species of 

 this wide-spread genus. 



Closely allied to the Langurs (Semnopithecus) is the 

 very curious Long-nosed or Proboscis-monkey of Borneo, 

 which seems to be confined to the lowlands near the 

 mouths of the rivers in Sarawak and the adjoining dis- 

 tricts of that island. It is the sole representative of the 

 genus Nasalis. 



Passing back to the Ethiopian Region, we find in the 

 place of Semnojyithecus and Nasalis the genus Colobus, 

 remarkable for the absence of a thumb on its hand, but 

 in other respects closely allied to its Asiatic brethren. 

 About ten species of Colobus are generally recognized by 

 naturalists. They are distributed all over the forests of 

 tropical Africa, being, perhaps, most abundant on the west 



