ii MR. SCLATER'S REGIONS 87 



dientia), Viverridae, Horses, or Antelopes, excepting Antilocapra, 

 a type of a separate division of Bovidae. But since several of 

 these groups have been represented in recent times, no primary 

 line of division can be profitably drawn. 



Arctogaea as a whole may be characterised by both negative 

 and positive characters. As negative features may be mentioned ; 

 the entire absence of Edentates (Necrodasypus of Pilhol is 

 rather doubtful, see p. 164, n.), though a few crept up into the 

 Nearctic region from Neogaea during past times ; and of Hapalidae, 

 Cebidae, and Marsupials, except an Opossum in North America. 

 This realm has, on the other hand, all the Lemurs, all the 

 Insectivores with the exception of the West Indian Solenodon, 

 all the Proboscidea, Rhinoceroses, Horses, Deer, Antelopes, the last 

 group including the Oxen and a variety of other important 

 families. It is in fact the headquarters of all the Eutheria with 

 the exception of the Edentata and Marsupials. 



The subdivisions of this realm have been variously effected. 

 The classical subdivisions are of course those of Mr. Sclater, who 

 would recognise (1) the Nearctic, North America ; (2) the Palae- 

 arctic, including Europe, Northern Asia, and Japan ; (3) the 

 Oriental, including Asia south of the Himalayas and the islands 

 of the Malay Archipelago as far east as the Australian region ; 

 and (4.) the Ethiopian, i.e. tropical Africa and Madagascar. Some 

 would alter this by uniting America and the north of the Old 

 World into a Holarctic region, separating off the southern parts 

 of the North American continent into a Sonoran region. To 

 some, the claims of Madagascar to form a separate region are 

 convincing. To distinguish the boundaries of the several regions 

 is a difficult task ; they dovetail into each other on the frontiers 

 with the complex curves of a puzzle-map. The difficulty has 

 been grappled with by the suggestion of intermediate transitional 

 areas ; but this proceeding really doubles the difficulty, for there 

 are then two frontiers to delimit in each case instead of 

 only one. The animal inhabitants must be expected to mingle 

 somewhat at the lines of junction of one region with another. 



The Sonoran region does not appear to us to have great claims 

 to recognition. It shows a mingling of southern with northern 

 forms exactly as might be expected. An Armadillo and Didelphys 

 have, as it is believed, invaded it from the Neogaeic realm ; it 

 possesses also the South American genera, Dicotyles, Nasua, Cone- 



