66 AFFINITIES AND HABITS OF THYLACOLEO, 



fibrous vegetable diet partaken of by those descendants from the 

 Phalangers which had more or less abandoned an arboreal life. 



Before considering the relations of ThylacoUo to this line of 

 forms with the enlarged premolars it will be necessary to look at 

 tlie much discussed question of the habits of the animal. Owen 

 has pointed out that in the large sharp-pointed incisors, together 

 with the powerful cutting premolars, we have a dental machinery 

 very similar to that found in the cat tribe — the large incisors 

 taking the place of the carnivore canines — " to pierce, retain and 

 Ivill "; and that such a dental machinery, though well adapted for 

 a carnivorous diet, would be quite unsuitable for any other; and 

 he has further shown that the structure of the jaw and the 

 cranium confirms the conclusion arrived at from a consideration 

 of the dentition. The main ai'gument of Falconer, Flower, 

 KrefFt, and Lydekker on the other hand in favour of Thylacoleo 

 being a herbivorous form is that practically all known Diproto- 

 dont Marsupials are herbivorous, or mainly herbivorous, 

 and that as Thylacoleo is a Diprotodont it most probably 

 likewise had mainly a vegetable diet. That this does not 

 unfairly represent the position will be seen from the pro- 

 position of Flower's already quoted, and from the following- 

 extract from Lydekker*: — "In originally describing this 

 remarkable animal from fragments of jaws containing the 

 fourth premolar, Sir Richard Owen came to the conclusion that 

 the structure of this tooth indicated a carnivorous animal adapted 

 to prey upon the huge Diprotodons and Nototheres ; but the 

 discovery of the complete skull has shown that the animal was 

 more closely allied to the existing Phalangers, and that it could 

 not have possessed the destructive habits attributed to it by its 

 describer, though it is quite possible that its diet may have 

 included the smaller mammals, birds, and eggs." Apart from the 

 exception which may be taken to the reasoning involved in this 

 statement, it in my opinion somewhat misrepresents Owen's 



* Manual of Palaeontology by Nicholson & Lydekker, 3rd Ed. Vol. ii. 

 1889, p. 1285. 



