106 ILLINOIS STATE ACADEMY OF SCIENCE 



its advance beyond them to greater morphological simi- 

 larity to the specialized diprotodonts. On the basis of 

 present findings, the only logical alternative would be 

 to remove the peramelids from the Polyprotodontia and 

 unite them with the coenolestids in a group co-ordinate 

 with (1) the Australian Diprotodontia and (2) the re- 

 maining Polyprotodontia. This, however, could not be 

 done consistently without further division, especially of 

 the polyprotodonts, which does not seem advisable in 

 the present state of knowledge." 



But regardless of the position of Coenolestes within 

 the marsupials, its brain is certainly an example of an 

 exceedingly simple and unspecialized mammalian brain, 

 perhaps the most generalized one we know. And as such 

 it stands closer to the line along which the Australian 

 diprotodonts have developed than do the more special- 

 ized polyprotodonts of America. 



