356 AN ELEMENTARY TEXT-BOOK OF BIOLOGY. 



regions, but in Madagascar and Australia only represented by 

 Muridce. They attain their largest development in S. America. 



The order is of great geological antiquity, for some living 

 genera extend back to the Eocene. Eodents probably originated 

 in the PalaBarctic region, whence migrations took place at an early 

 date to S. America and S. Africa, allowing time for great special- 

 ization. 



7. Proboscidea. Elephants are now limited to the Ethiopian 

 and Oriental regions, but formerly had a much wider extension. 



Pala3arctic forms occur from Miocene to Pleistocene times, 

 and elephants have lived in India since the Miocene period. 

 Numerous fossil examples occur in the Pliocene and Pleistocene 

 deposits of N. and S. America. 



8. Hyracoidea. Almost entirely limited to the Ethiopian region, 

 but range northwards as far as Syria. 



9. Insectivora. Very widely distributed, and represented by 

 numerous specialized forms. Absent from S. America and 

 Australia. 



This order is a very ancient one, as shown by the fact that 

 Miocene forms mostly belong to existing families. Extinction 

 appears to be slowly taking place, and has led to many cases of 

 discontinuous distribution e.g., Centetidce, represented by Solenodon 

 in the W. Indies, and Centetes, with four other genera, in Mada- 

 gascar. 



10. Cheiroptera. Bats, as might be expected, are found in all 

 the great areas, but the Frugivora are absent from the Nearctic 

 and Neotropical regions, as are the Horse-shoe bats (Rhinolophidce) 

 among insectivorous forms. On the other hand, the Leaf-nosed 

 bats (Phyllostomidce) are almost exclusively Neotropical. 



Fossil bats, very like recent species, date from Eocene times, 

 and the order is undoubtedly one of extreme antiquity. 



1 1. Carnivora. (a) Fissipedia. Occur in all the regions, except, 

 perhaps, the Australian (the " native dog " of Australia is only 

 doubtfully indigenous), but are especially characteristic of the 

 Ethiopian and Oriental, which possess almost all the Fiverridce 

 and HycenidcK, with a great many of the Felidce and Mustelidce. 

 Two genera, Cryptoprocta and Proteles, constituting distinct 

 families, are limited respectively to Madagascar and S. Africa. 

 Bears, however, are absent from the Ethiopian region, and are 

 only represented by one species in the Neotropical region, which 



