MONOTREMATA AND MAESUPIALIA. 



297 



presence in either jaw of a huge, compressed, and trenchant 

 praemolar. The dental formula is — 



. 1- 



-1 1—1 8 — 3 



-^ ; c ; 2Jm 



-3 0-0 1—1 



m ^24. 



2—2 



The incisors are not horizontal, as in the Kangaroos, but 

 resemble those of the Phalangers, and the true molars are 

 very small. Nothing is laiown of the skeleton of Thyiacoleo 

 beyond the skull ; and the peculiar dentition has been dif- 

 ferently interpreted by different authorities. By Professor 

 Owen it is believed that Thyiacoleo was flesh-eating and 

 predatory in its habits, and that it represents a type of Dipro- 



Fig. 609.— Skull of Thyiacoleo. Post-Tertiary deposits of Australia. (After Flower.) 



todonts specially modified in accordance with the carnivor- 

 ous mode of life. Professor Flower, on the other hand, com- 

 pares the cutting prsemolar with the correspondingly de- 

 veloped tooth in Hypsi-prymnus, and concludes that " Thyia- 

 coleo is a highly-modified and aberrant form of the type of 

 Marsupials now represented by the Macropodidm and Plialan- 

 gistida'., though not belonging to either of these families as 

 now restricted," and he believes that its diet was of a ve2;e- 

 table nature. Under any view of its habits, Thyiacoleo is a 



