E. LÖNNBERG, MAMMALOGY OF ECUADOR. 93 



are such animals as Kangaroos, Wombats etc. and on the 

 other side not all Polyprotodonts can be termed plantigrade. 

 With regard to number of pads the hallucal pad af Caenolestes 

 is divided, so that the total number of plantar pads becomes 

 6, and in this respect it resembles, as Thomas has pointed 

 out, Phascologale wallacei, but six pads on the hind feet is 

 certainly not a common feature of Polyprotodonts, as not 

 even all members of Phascologale have that number. A »claw- 

 less thumb» is of course just as little a Polyprotodont cha- 

 racteristic. It is evident, that if a characteristic shall be 

 allowed to be termed polyprotodont it ought to be common 

 to all such animals, or at least shared by the majority of 

 them in opposition to the condition found in the Diproto- 

 donts. This is, however, not the case with those that have 

 been quoted by Miss Dederer. 



Therefore the present author cannot agree with Dr. 

 Broom when he terms ^ them to be of »great importance.» 

 Dr. Broom points out as »important» differences between 

 Caeriolestes and the Diprotodonts the following characteristics: 

 None of the latter has more than three incisors, while Cae- 

 nolestes has four, and further is the canine when present in 

 Diprotodonts »always of less importance than the incisors», 

 while in Caenolestes the upper canine is larger than the in- 

 cisors. When the author quoted on the same page speaks 

 about, how easily in some cases dentition can be altered (ef. 

 below), it appears stränge, that he in this connection has 

 not considered, that reduction is a change, which may take 

 place more easily than any other. In fact, Orolestes, the 

 recently by Thomas described, with Caenolestes closely related 

 genus shows such a reduction in size of the fourth incisor 

 and of the canine. It presents thus a condition, which 

 approaches that of the typical Diprotodonts still more than 



Caenolestes. 



Dr. Broom expresses his views with the following words: 

 »Apart from the condition of the teeth, Caenolestes is a ty- 

 pical Polyprotodont in all its cranial characters»^ and there- 

 fore it appears doubtful to him, »whether the Diprotodont- 

 like character of the teeth is of sufficient weight to place 



1 Proc. Lin. Soc. N. S. W. Vol. 36 Sydney 1911, p. 318. 



2 When saying this he probably accepts and overestimates Mibs ue- 

 derer's arguments, which already have been discussed above. 



