5613 



ZOOLOGY 



SECT. 



poorly represented in Australia and Madagascar. The Rodents 

 reach their greatest development, as regards the number of 

 families, in South America, in which region occur also the majority 

 of the largest members of the order. 



Insectivora are absent in the Australian, Polynesian, and New 

 Zealand regions, and in South America ; but occur in all the other 

 provinces. The Chiroptera are world-wide in distribution, occurring 

 in greatest abundance in tropical and warm temperate zones. The 

 Flying Foxes (Pteropidse) are absent from the Nearctic and 

 Neotropical regions, and the Vampire Bats occur exclusively in the 

 latter. 



The distribution of the Lemurs is remarkable ; they occur only 

 in Madagascar, a limited part of South Africa, Southern India and 

 Ceylon, some of the islands of the Malay Archipelago, and the 

 Philippines. The headquarters of the group is the island of 

 Madagascar, of which the}* constitute one-half of the entire 

 Mammalian fauna. 



Of the other groups of Primates, the Marmosets (Hapalidse) and 

 the Cebidse are exclusively American : the Cercopithecidae Palae- 

 arctic, Oriental and Ethiopian, with a single species in Mada- 

 gascar. Of the Simiidae the Gibbons occur only in South-Eastern 

 Asia and the Malay Peninsula ; the Orangs only in Borneo and 

 Sumatra ; the Gorilla and Chimpanzee in certain parts of Western 

 Equatorial Africa. 



The earliest fossil-remains of Mammals have been found in strata 

 of Upper Triassic and of Jurassic age in Europe and America, 

 These remains consist almost exclusively of jaws and teeth, and, 



Fin. ll.jS. PhasCOlotherium bucklandi. Inner view of right ramus of mandible. (After 



Owen.) 



as the latter differ widely from those of existing Mammals, there 

 is frequently great difficulty, in the abs nee of remains of the 

 other hard parts, in determining the affin ties of these Mesozoic 

 forms. Some of the Triassic and Jurassic Mammalian molar teeth 

 are constructed on the most primitive form of the triconodont type, 

 which has already been referred to (p. 529) as being the primitive 



