54 (iiEOLOGICAL SURVEY OF TfiXAS. 



BOROPIIAGUS DIVERSIDENS, Cope. 



Plate XIII, Figure 4. American Naturalist, 1892, p. 1028. 



Represented by the anterior part of the left mandibular ramus with 

 two premolar teeth in place, and the alveoli of the anterior and of the 

 canine. Another specimen included the separate crowns of three molars, 

 including part of the sectorial, but the specimen is unfortunately at this 

 time mislaid. 



Owing to the absence of the entire dental series it is uncertain whether 

 there are three or four premolars. The alveolus of the canine indicates 

 a very large tooth, with the posterior face of the root broadly rounded. 

 The fourth premolar has one alveolus, which is round, and is in immedi- 

 ate contact with that of the canine. The third premolar is three rooted, 

 and the anterior root is separated by a short space from that of the fourth. 

 The crown is obtuse and molariform, and is traversed by a low median 

 longitudinal keel, whose direction is diagonal to the long axis of the jaw, 

 and which has only a faint indication of a median cusp. The crown of the 

 second premolar (first?) is much elevated and very robust. It consists of 

 an anterior conic cusp, whose horizontal section at the base is a wide oval, 

 a lobe of the posterior margin, and probably a large keel, but this is 

 broken off. The posterior root is very large, its alveolus nearly equal- 

 ing that of the canine. I infer from this the presence of a large keel, 

 wider than long. This tooth has no anterior cutting edge, but an angu- 

 lar trace of one. The third premolar crown only reaches the base of the 

 crown of the second. The mental foramen is below the space between 

 the third and fourth premolars. 



Measurements . 



Mm. 



Transverse diameter canine alveolus 13 



Transverse diameter second alveolus, P. m. ii 13 



lougitudiual 4 



Diameters crown P. m. iii \ anteroposterior 10 



transverse 8 



longitudinal 17 



Diameters crown of P. m. ii \ anteroposterior * 28 



transverse 15 



The second specimen includes a robust conic crown with a small conic 

 cusp at its base, and an anterior blade of a sectorial. The conic cusp is 

 without cutting edge. The blade has a rather short straight edge, which 

 is in its unworn state finely serrate. It is no larger than the correspond- 

 ing part in the ^lurodon saevus. 



This remarkable species was probably a scavenger, devouring the car- 



*Partly estimated on account of absence of keel. 



