640 land mammals in the western hemisphere 



Suborder Diprotodonta 



North America never had any representatives of this 

 suborder, but South America possessed many of them in the 

 Santa Cruz Miocene and one genus (Ccenolestes) has survived 

 to the present time. Austraha, on the other hand, has three 

 well-defined families of the suborder, the kangaroos, phalangers 

 and wombats, but no member of any of these has ever been 

 found outside of the Australian region. So far as we know, 

 therefore, the suborder is and always has been confined to 

 the southern hemisphere. 



The modern South American genus Ccenolestes is a small, 

 rat-like animal and very rare ; it has been found only in Ecuador 



and Colombia. Its denti- 

 tion is not at all typically 

 diprotodont, but rather 

 intermediate in character 

 between the latter and the 

 Polyprotodonta. The 



Fig. 301 -Skull oiC.nolestes ohscurus, en- ^^^^^j formula is I 1 |, C \, 

 larged. (After Sinclair.) ^' i' 



7^1, m{, X2 = 46. The 

 upper incisors are small and of subequal size, though the 

 second is somewhat the largest of the series, and the canine 

 is considerably larger and more prominent than any of them. 

 The foremost lower incisor is long and pointed and directed 

 almost straight forward ; the other lower incisors and the 

 canine are minute and can have little or no functional 

 value. The premolars are small and simple and the upper 

 molars quadritubercular, the third one triangular, and the 

 fourth very small and apparently about to disappear. Such 

 teeth would seem to indicate a vegetable diet, but it is reported 

 that the animal subsists chiefly upon small birds and their 

 eggs. The skull, which is typically marsupial in all its char- 

 acters, is most like that of the smaller Australian native cats 

 (Dasyuridse) and the feet show no signs of the syndactyly 



