MARSUPIALIA. 171 



larger than the second. The arrangement of the cusps is alternating on 

 opposite sides of a median groove. The grooves are deep, and resemble 

 the impression of a simply pinnate leaf with alternating leaflets. 



The coronoid process rises opposite the second molar. The inferior 

 face of the posterior part of the ramus is flat, owing to both internal and 

 external inflections. Both ai-e well marked, the latter bounding the masse- 

 teric fossa, which is open in front, and without foramen. The internal in- 

 flection bounds a deep fossa, like that seen in Hypsiprymnus and Macropus 

 to terminate in the dental foramen. 



The only species of this genus known to me is from the Puerco 

 horizon. 



Catopsalis foliatus Cope. 



American Naturalist, 1882, p. 416, April 24. 

 Plate XXXIII c; fig. 2. 



The mandibular ramus which represents this animal is robust and deep. 

 The alveolar line rises from behind forwards, as in Elephantidce and various 

 rodents, and then suddenly descends. The inner side of the ramus is con- 

 cave, while the external side, anterior to the masseteric fossa, is convex. 

 The incisive alveolus is thus thrown inside the line of the molars in front. 

 There is a large fossa exposed by weathering below and behind the last 

 molar, which is identical with that seen in Hypsiprymnus and Macropus, and 

 indicates a large dental foramen. 



Below the middle of the fourth premolar footh the incisor tooth is quite 

 large, suggesting whether it had not a persistent growth, as in the Rodentia. 

 The posterior cusp of the fourth premolar is triangular in profile, the ante- 

 rior edge descending steeply. It is uncertain whether the edge of the crown 

 rises again, forming another lobe. The apex of the cusp is conic. The first 

 true molar is of large size and remarkable form. The crown viewed from 

 above is a long oval. It has a deep median longitudinal groove, which 

 sends out branch grooves alternately and at right angles to the edge. The 

 spaces between the grooves form block-shaped tubercles, four on the inner 

 and five on the outer sides, whose transverse diameter generally exceeds 

 their anteroposterior. The median groove is open at its anterior extremity. 



