60 ' AFFINITIES AiXD HABITS OF THYLACOLEO, 



observable in comparing large with small species of a natural 

 group."* Having dealt with its affinities, Flower proceeds to 

 consider the pi'obable habits of this animal which Owen had 

 supposed to be a sort of pouched-lion. Towards the solution of 

 this question he propounds the following proposition which he 

 thinks will be generally accepted : — " That if all the known 

 species of a large group of animals with teeth formed on one 

 peculiar type lead lives peaceable and inoffensive to their neigh- 

 bours, and feed mainly on vegetable substances, the probabilities, 

 in the case of any newly discovered species having teeth con- 

 structed on the same general type, are greatly in favour of its 

 having possessed similar habits and been nourished by a corres- 

 ponding diet."t Assuming this proposition to be correct, he has 

 no difficulty, after having settled its affinities, in concluding that 

 Thylacoleo was a vegetable feeder, and he considers that there is 

 no reason why the large premolar should not have been " as well 

 adapted for chopping up succulent roots and vegetables as for 

 dividing the nutritive fibres of animal prey."| He also states 

 the food of Thj/Jacoleo " may have been some kind of root or 

 bulb; it may have been fruit; it may have been flesh " § ; but he 

 does not consider that the organisation of the animal suited it 

 for preying on the large Diprotodonts. 



Some years before the publication of Flower's paper. Falconer, || 

 in dealing with the probable habits of Plagiaulax, which Owen 

 had regarded as a carnivorous form, set forth a number of argu- 

 ments in favour of its being a herbi^'ore, very similar to those 

 which Flower has applied to Thylacoleo, so that though Falconer 

 apparently agreed with Owen as to the habits of Thylacoleo, his 

 various arguments if applied would more logically make him a 

 supporter of Flower's position. 



* hoc. cit. p. 311. 

 t Loc. cit. p. 315. 

 J Loc. cit. p. 318. 

 § Loc. cit. p. 318. 

 II "On the disputed affinity of tiie Mammalian Genus, Plagiaulax, from 

 the Purbeck Beds." Q.J.G.S. 18G2, xviii. p. .S84. 



