MAY, 1921. AMERICAN MARSUPIAL, C^ENOLESTES OSGOOD. 9 



ports avec les Garzonidae qu'avec les Epanorthidae. Pourtant il est 

 probable que le Coenolestes devra constituer le type d'une famille nou~ 

 velle." 



Accepting the suggestion of Ameghino and others, Trouessart 

 (1898) gave it the rank of a family, the Caenolestidae, including only 

 the one genus, and assigned it to the suborder Diprotodontia. Ameghino 

 (1900) later treated it as a family of diprotodonts, and still later (1903), 

 in his well known rearrangement of marsupials and rodents, he included 

 in the family the genus Ccenolestes and also the extinct genus Zygolestes. 

 The family was classified with four others, containing only extinct 

 forms, in his suborder Paucituberculata, which in turn was referred to 

 the order Plagiaulacoidea and regarded as directly ancestral to the 

 Australian diprotodonts. The name Diprotodonta was reserved to 

 designate a superorder conceived to embrace not only American and 

 Australian diprotodonts but also the multituberculates and the rodents. 

 Although Ameghino's ideas have not been generally accepted, especially 

 those regarding the derivation of rodents, his strong conviction of the 

 close alliance of American and Australian diprotodonts is noteworthy 

 in the present connection. While differing from him in other respects, 

 Weber (1904) agreed with Ameghino in placing Canolestes in neither the 

 Diprotodontia nor the Polyprodontia but in a third suborder of marsu- 

 pials for which Ameghino's name Paucituberculata was available. Mean- 

 while, Bensley (1903), in his very important paper on the evolution of 

 Australian marsupials, included C&nolestes in his "First Neogseic 

 Radiation" and in casual references indicated his belief that its dentition 

 is due to parallel or convergent development rather than to any direct 

 relationship to Australian diprotodonts closer than that of common 

 derivation from a didelphid ancestry. 



On the other hand, Sinclair (1905, 1906) and Scott (1913) revert to 

 the opinion of Thomas and Ameghino that Ccenolestes and allied extinct 

 forms are so closely related to Australian diprotodonts as to furnish 

 strong evidence of a former land connection between South America 

 and Australia. Sinclair includes all South American forms with diproto- 

 dont dentition in the family Casnolestidae which he divides into two sub- 

 families, of which the Caenolestinae embraces the genera Ccznolestes, 

 Garzonia, and Halmariphus. Of this family he says (1905): "The 

 Caenolestidae resemble the primitive phalangers in so many respects 

 that it is impossible to escape the conclusion that the two families are 

 related and not merely convergent groups." This statement is some- 

 what modified in a later paper (1906), as follows: 'While substantially 

 the same conclusions are still held, it is proper to point out the evidence 

 in favor of the view that the striking similarity in dental structure 



