170 Tin: WASATCH AND BRIDGER FAUX.E. 



lierbivorous, Thijlacolco is so also. Professor Flower refers to the absence 

 of molars in ThylacoJeo as slifrhtly complicating the problem, and concludes 

 that the food of that animal may have been fruit or juicy roots, or even 

 meat. It is difficult to imagine what kind of vegetable food could have 

 been apjiropriated by such a dentition as that of PtUodus and Thylacoleo. 

 The sharp thin serrate or smooth edges are adapted for making cuts, and 

 for dividing food into pieces. That these pieces were probably swallowed 

 whole, is indicated by the small size and weak structure of the molar teeth, 

 which are not adapted for crushing or grinding. It is not necessaiy to sup- 

 |)0se that the dentition was used on the same kind of food in the large and 

 the small species. In PtUodus medioEVUs the diet may have consisted of 

 small eggs which were picked up by the incisors and cut by the fourth pre- 

 molar. In Thylacoleo it might have been larger eggs, as those of crocodiles, 

 or carrion, or even the weaker living animals. The objection to the suppo- 

 sition that the food consisted of vegetables, is found in the necessity of 

 swallowing the pieces without mastication. In case it could have been of a 

 vegetable character, the peculiar teeth would cut off pieces of fruits and 

 other soft parts as suggested by Professor Flower, but that these genera 

 could have been herbivorous in the manner of the existing Macropodidcc, 

 with their full series of molars in both jaws, is clearly inadmissible. 



CATOPSALIS Cope. 



American Naturalist, May, IStCJ (April 24), page 416. 



This genus is known from a part of a mandibular ramus with a few 

 other bones associated. The jaw is broken off in front of the fourth pre- 

 molar, and the fracture displays the shaft of a large incisor tooth. It is im- 

 possible to state how many premolars there are. The fourth is of large 

 size, and is exceedingly compressed. The alveolar border descends abruptly 

 from its posterior root, having the outline of the diastema of the jaw in 

 various rodents, where, however, it is edentulous. The result of this form 

 is, that the crown is presented forwards in an acute edge. The inferior two- 

 thirds of this edge is broken off, so lliat it is not possible to state whether it 

 is grooved or serrate. The superior part is neither, mul rises into a cusp 

 posteriorly. The two molar teeth are very peculiar, aiwl tlie first is much 



