6o2 GEOGRAPHICAL DISTRIBUTION 



and North America north of (5); (5) Sonoran — roughly 

 corresponding to greater part of United States. 



I. Madagascar Region, comprising Madagascar, Mau- 

 ritius, Bourbon, Rodriguez, Seychelles and Cornova Islands. 

 — The mammalian fauna of Madagascar is so remarkable 

 that it has strong claims for being placed in a region apart 

 from Africa. The most striking feature is the huge quantity 

 and variety of lemurs, representing three families and nearly 

 forty known species. The allied order of Insectivora is 

 represented by a large and unique family, the Cenfetidce^ in 

 addition to a probable immigrant, the musk-shrew, and one 

 potamogale. A cat-like carnivore {Crypfoprocta) and a 

 number of mongooses represent the Carnivora, all belonging 

 to the civet family {Viverridce). There are in the case of 

 Notogoea about seven species of the cosmopolitan Muridce, 

 of the Rodentia^ and the list is completed by the bush-pig. 

 We may note also the fox-bats {Fieropus) and an extinct 

 Hippopotamus. 



Lemurs, insectivores, carnivores and rodents occur on 

 the mainland of Africa, but none of the genera found in 

 Madagascar. Indeed, the only genera common to the two 

 regions are the bush-pig and hippopotamus and the musk- 

 shrew. The latter was probably introduced at a later date, 

 and the two former probably introduced themselves by swim- 

 ming, possibly at a date when the strait was of narrower 

 dimensions than now. 



Madagascar has the monopoly of the following families : 

 — The Chiromyidce (Aye-Aye) and CentetidcE (Tenrecs), and 

 by some authorities the " Foussa" {Cryptoprodd) is placed 

 in a family by itself. 



Almost as strange as these inhabitants is the entire 

 absence of all the characteristic African mammals, the large 

 Ungulata and Carnivora. 



The usually accepted explanation of these peculiarities is the as- 

 sumption that Madagascar has been isolated from the mainland of 

 Africa from early Miocene or upper Oligocene. In the Oligocene the 

 lemurs flourished in Europe, as also the civets ; and a separation effected 

 at this period might easily isolate a sample of these two groups, together 

 with the primitive Insectivora, whilst the modern Ungulata and Carni- 

 vora of Africa would not by then have reached that region. Hence the 

 history of Madagascar is a more recent repetition on a smaller scale of 

 the history of Notogoea. Occurring later, it merely serves to preserve 



