Tooth-marls of Thylacoleo. 107 



(Fig. lA, Plate XXXIX.). Fig. 11, Plate XXXVII., represents 

 the cut made in clay by the pressure of the upper left tooth, 

 and it will be seen how closely the angle agrees with that of 

 the actual bone specimen. In Fig. 14, Plate XXXVII., the 

 edge (b) of the bone shows a fracture, but in Fig. 13, Plate 

 XXXVII., which was apparently cut by the right upper tooth, 

 both the cut surface (a) and the edge (b) are definite incisions. 



Attention may here be drawn to the fact that, in the case 

 of the upper premolar (Plate XXXIX., Fig. 1a), the cutting ridge 

 is divided into two parts inclined at an open angle to one another, 

 whilst, in the lower premolar (Plate XXXIX., Fig. 2a), the line 

 of the ridge forms a continuous curve. Diflerences due to these 

 facts are expressed in the more curved or slightly angular cuts 

 made respectively by these teeth. 



While the results of the experiments with clay have shed 

 considerable light upon the problem we have attempted to 

 solve, it is not held that they represent exactly what has taken 

 place in the original operations. The difference in the nature 

 of the material employed alone might lead to erroneous con- 

 clusions, owing to the modelling clay yielding so readily to 

 pressure and simulating forms which perhaps would not be 

 obtained if the natural material had been used. 



Taken in conjunction, however, with the repetition of many 

 general features and details in the specimens which we have 

 been able to reproduce, the experiments certainly seem to bear 

 out the assumption that Thylacoleo was, as far as it is possible 

 to ascertain, the cause of the reimarkable human-like sculptur- 

 ing and fragmentary condition of the bones. 



It should be mentioned that a careful examination of teeth- 

 marks on bones convinced us that Thylacoleo had fractured 

 some of them, by a chopping action of its teeth directed on, or 

 very close to, the same spot. A study of the surfaces of the 

 specimens completely sliced without fracture reveals the fact 

 that what appears at first sight in two or three cases — for 

 example. Fig. 14, Plate XXXVII. — to be a face produced by a 

 single continuous application of a cutting instrument, is really made 

 up of several facets. In these instances it seems as if sever- 

 ance had been effected by this chopping action of the teeth od 

 the bones, delivered at the same angle and in the same line. 



