204 EASTERN ARCTOG^A. [CHAP. 



in having only four columns on the crowns of the molars, as 

 shown in the annexed figure, and thus presenting a marked 

 approximation to the ruminants. The earlier Tertiary Chczropo- 

 tamidcz likewise had a survivor in the genus Tetraconodon, which 

 was represented by a large pig-like creature remarkable for the 

 enormous size of its simple conical premolar teeth. The pig- 

 like group closes with Hippopotamus, which makes its appearance 

 on the scene for the first time in this formation, where it is 

 represented by a generalised species with three pairs of incisor 

 teeth in each jaw. Turning to the groups with fully-developed 

 selenodont molars, we have first to notice the occurrence of fossil 

 camels of the existing genus Camelus, which are unknown else- 

 where except in the Algerian Plistocene. As we have seen that 

 the Camelidce. were originally a New World group, it is interesting 

 to note that these earliest Old World representatives occur in Asia 

 instead of Europe; and it is further noteworthy that in the 

 structure of their molar teeth the Siwalik camels retain evidences of 

 affinity with the South American guanacos and vicunas which are 

 lost in their living descendants. The Tragulidce contain repre- 

 sentatives of the true chevrotains ( Tragulus) and water-chevrotains 

 (Dorcatherium\ now respectively characteristic of the Oriental and 

 Ethiopian regions, while among the deer ( Cervidce) we have species 

 of the Oligocene European genus Palaomeryx, together with 

 others belonging to Cervus, the representatives of the latter being 

 all closely allied to existing Oriental types. Not improbably also 

 a musk-deer (Moschus) should be included among the Siwalik 

 Cervidce. Among the Giraffidce, in addition to true giraffes 

 (Giro/a), which are common to the Pikermi beds, and extended 

 eastwards into China, we have the peculiar gigantic antlered types re- 

 spectively known as Vishnutherium, Sivatherium, Hydaspotherium, 

 and Bramatherium, of which the first seems common to the Siwaliks 

 of Burma and the Punjab, while the second is confined to the 

 more easterly Himalaya, the third to the Punjab, and the fourth to 

 Perim Island. They include the most gigantic of all ruminants, 

 Sivatherium almost rivalling an elephant in bulk. 



Not one of the least curious features in this marvellous fauna is 

 that while, as we have seen, deer of Oriental types were abundant, 

 antelopes closely allied to those now inhabiting the Ethiopian 



