1882.] 4:t>i [Cope. 



ECTOCYNODON AGUTI, Sp. nOV. 



This reptile is much larger than the Pariotichus hracTiyops, and the ante- 

 rior part of the cranium has a diScrent form. The general shape of the 

 head is much like that of a rodent mammal of the genus Dasyprocta. It 

 is rather wide at the temporal regions, flat above, and narrowed and com- 

 pressed anterior to the orbits. The muzzle is narrowed and obtuse, and 

 the nostrils are terminal, and are lateral and a little anterior in direction. 

 The maxillary alveolar edge is nearly straight, but the premaxillary edge, 

 beginning below the posterior border of the nares, descends forward at 

 an angle of 45°. Viewed from the front, the premaxillarj^ border is a 

 festoon, strongly convex downwards, and below the anterior part of the 

 nostril. The suture separating the premaxillaries is distinct. The orbits 

 are of moderate size, as in an aguti, and invade the superior frontal plane 

 in a slight degree. The frontoparietal fontanelle is rather large. 



The mandible is robust, and presents a short angle. It closes up behind 

 the premaxillary lobate edge. Its teeth are concealed in the specimen. 

 The maxillary teeth increase rapidly in size forwards. The premaxillaries 

 commence smaller next the maxillaries, and increase in size to the first, 

 which is a little larger than the anterior maxillary. The crowns are 

 weathered away. The sculpture on the maxillary and malar bones con- 

 sists of closely placed shallow fossae. On the posterior part of the frontals 

 there are strong ridges radiating posteriorly, and situated close together. 

 Measurements. M. 



Length of skull to end of angle of lower jaw 090 



" " frontoparietal fontanelle 056 



orbit, above 026 



" ramus mandibuli 083 



Depth of skull at orbit , 033 



" ramus " 019 



Width of skull posteriorly 068 



" " between orbits 017 



" " between external nares 0105 



Diameter of first premaxillary tooth .003 



' ' second maxillary tooth 003 



Six fossae of the malar bone 005 



Seven grooves of the frontal bone 005 



This species is much larger than the Ectocynodon ordinatus Cope, and 

 the canine tooth has a more anterior position. 

 Discovered by W. F. Cummins. 



DIPLOCAULUS Cope. 



Paleontological Bulletin No. 26, p. 187, Nov. 21st, 1877. Proceedings 

 American Philos. Society. 1877, p. 187. 



This genus was characterized by me at the places cited, as follows: 

 " Vertebral centra elongate, contracted medially, and perforated by the 



PROC. A5IER. PHILOS. SOC. XX. 112. 3b. PRINTED NOVEMBER 17, 1882. 



