Mammalia: Classification 



-.',:, 



Order 3: DIPROTODONTIA. Dentition of herbivorous type- 

 usually two and never more than three pairs of chisel-like incisors in 

 upper jaw and one pair in lower, the middle pairs being very strongly- 

 developed; canines small or lacking; molars of crushing type, some- 

 limes ridged. 



Examples: Kangaroos and the smaller kangaroo-like wallabies 



(Family Macropodidae) ; dental formula for kangaroo (Macropus), 



.31 2 4 



i y, c ~, p ^, m -; the wombat (Phascolomys); phalangers and the 



bearlike koala (Phalangeridae) mainly arboreal: (Figs. 539-542). 



Distribution. Marsupials are found in Australia, Tasmania, New 

 Guinea, and some other islands of that region, but not in New Zealand, 

 and nowhere else except that the opossums (Didelphidae) occur in 

 South America and southeastern North America, and the small, 

 obscure, rodent-like Caenolestes is found in South America. 



Fig. 541 (Left). Phalanger or Australian opossum. (Courtesy, American Museum 



of Natural History, New York.) 



Fig. 542 (Right). Koala, Phascolarctos cinereus. (Courtesy, American Museum of 



Natural History, New York.) 



