R. Lydel-ker — Distribution of the Sitmlilc Fauna. 491 



Among the existing genera, exclusive of the cosmopolitan forms, 

 the most noticeable feature is the large number of those which are 

 confined at the present day either to both, or one or other of the 

 Ethiopian and Oriental regions. Some of these genera are also 

 found in the Tertiaries of Europe ; but others have never been 

 recorded beyond the limits of the Ethiopian and Oriental regions ; 

 whence it may be concluded that they have very probably always 

 been mainly confined to those regions. 



All this is in perfect accord with the now generally received 

 hypothesis that the higher mammals of the Ethiopian region are 

 comparatively recent immigrants from the Euro-Asiatic continent ; 

 and it also leads to the conclusion as to the essential unity of the 

 higher mammalian faunas of the Ethiopian and Oriental regions ; 

 the present extinction of many Ethiopian forms in the Oriental 

 region being, so to speak, an accident of the present period. Why 

 the members of the first group (a) in the table have apparently 

 never extended to the Ethiopian region ; and why those of the 

 second (6) have totally disappeared from the Oriental region, are 

 questions exceedingly difficult, if not impossible, to answer. In 

 regard to the second group, it is just possible that as a field is after 

 a time more or less incapable of bearing the same kind of crop, so 

 a country may become incapable of supporting the same kind of 

 animal for a very extended period ; and thus many forms have 

 disappeared from their old Oriental haunts, but have persisted in 

 the newer field of the Ethiopian region. That the Glacial period, 

 even if it had any appreciable effect in the plains of India, should 

 have led to the extirpation of the Giraffe and the Hippopotamus, 

 while the Elephant and the Rhinoceros survived, seems incredible. 



The occurrence of struthioids in the Siwaliks, although not of 

 itself leading to the same conclusion, presents no opposition to the 

 conclusions of Mr. Wallace^ that these birds were widely distributed 

 at a comparatively early period, and had reached Africa long before 

 the period of the immigration of the larger mammals. The close 

 resemblance of the Siwalik to the existing Ostrich may, however, 

 suggest that this particular genus gained access to Africa at the 

 same time as the larger mammals. Manis is probably a member of 

 the primitive fauna of both the Oriental and Ethiopian regions. 



Among the extinct genera a considerable number are common to 

 the Tertiaries of Europe, and these, taken with the existing Siwalik 

 genera found in the same region, indicate the general similarity of 

 the earlier mammalian faunas of the Palcearctic and Oriental regions. 

 There are, however, a large number of extinct genera peculiar to the 

 Siwaliks ; although several of them are closely allied to European 

 forms. JPalceopitheciis is of especial interest, as confirming the 

 opinion that the Euro- Asiatic continent was the original home of the 

 larger anthropoids.^ Hemibos is doubtless an ancestral form of the 

 living Anoa ; and it thus serves to connect the fauna of Celebes with 

 that of the Oriental region. 



1 Vide "Island Life," pp. 408-9 (1880). 



2 I desire to retract all belief iu " Lemiuia " ; to wliich I h.ad resource in my 

 description of falmopithecus. 



