108 



GOPE 



The Marsupialia fall into two suborders, which differ as 

 follows : 



Incisors |^ 

 Incisors [^ 



Polyprotodontia. 

 Diprotodontia. 



The Polyprotodontia are carnivorous and insectivorous 

 in their habits, and their present range is Australasia and 

 the two Americas. They are the older of the suborders, 

 being represented in the Eocenes of Europe and North 

 America by spe- 

 cies of opossums j^^S^X^ <^ '^ '^ ^ h 

 (Fig. 43). Genera WZl^^^f&S^ s-^-'. 

 probably allied oc- 

 cur in the Post- 

 cretacic of North 

 America. No large 

 forms are known. ^ " ({ 



The Diprotodontia /'f • ^^-P^o.I^~ f^a^^ cope ; anterior part of 

 ^ skull. From Lower Neocene (White River bed) of 



are now restrict- Colorado. X 2. original. 



ed to Australasia, and the extinct forms belong to the Plis- 

 tocene of the same region. These include some very large 

 kangaroos, with still larger animals of the genera Noto- 

 therium and Diprotodon. The Diprotodon australis Owen 

 was as large as a rhinoceros, but though allied to the kan- 

 garoo, was typical of a different family. The feet were 

 plantigrade, and the fore limbs were larger than the hind 

 limbs. 



The Cetacea are represented by three suborders, which 

 differ as follows : 



External nostrils at middle of muzzle ; 

 temporal fossse elongate, approxi- 

 mated; teeth ; Archseoceti. 



External nostrils at base of muzzle ; tem- 

 poral fossse short, lateral ; teeth ; Odontoceti. 



