614 GEOLOGICAL SUEVEY OF THE TEREITORIES. 



states the vertebrae to be " strongly rugose" near the extremity, a 

 character not seen in the present animal. 



The Biplocynodus subulatm was about as large as the Mississippi 

 alligator. 



DiPLOCYNODUS POLY'ODON, Cope. 



Species nova. 



Eepresented by portions of cranium and teeth, with probably some 

 vertebrae found close to them. This crocodile is similar in size to the 

 J), subulatus, or our alligator. It differs much from the last in the ar- 

 rangement of the teeth. There is one pre-eminently large canine oppo- 

 site the symphysis, (in JD. subulatus this tooth is opposite the posterior 

 end of the same,) which is followed by nine very Small teeth, whose 

 rouiKl alveoli are only separated by very thin walls. Following the last 

 of these immediately is another very large tooth, with nearly round 

 alveolus, which is closely succeeded by other smaller teeth of larger 

 size than those in front of it, and not differing in this respect among 

 themselves. The crowns of the teeth are cylindric at base, and have 

 a double ridge on the anterior outer a-spect. The enamel is obsoletely 

 rugose, striate at the base. The external surface of the dentary bone is 

 deeply and coarsely pitted; at its anterior part the pits are close, deep, 

 and small; on the inferior face they are deep, short grooves. There is 

 a series of close, small foramina along the inner side of the alveolae. 



Measurements. 



M. 

 Depth of symphysis 0. 014 



Diameter " anterior canine tooth" . 003 



Distance of same from median " canine" 030 



Depth dentary hone at latter 027 



Width ramus at anterior canine 025 



This species differs in many respects fi^om the one last described. The 

 teeth, anteriorly, are much more closely placed, and the anterior and 

 middle canines are less separated, and more numerous small teeth occupy 

 the interval. The splenial bone has a larger share in the symphysis, and 

 the sculpture is much more profound. The teeth are not fluted. 



The type specimen was found on the bluffs of Upper Green Eiver by 

 the writer. 



ALLIGATOE, Cuv. 



The species described below belongs to this genus, so far as determin- 

 able from characters of the cranium and dermal scuta. • 



The axial portion of the basi-occipital bone is a transverse vertical 

 plate with vertical carina on the distal half. The frontal bone exhibits 

 no crests, and the crotaphite foramina are open. The quadratojngal 

 arch is stout. The dermal scuta are not co-ossified, and with the cranium 

 are deeply pitted. 



Alligator heterodon, Cope. 



Proceedings American Philosophical Society, 1872, p. 544. 



The anterior and posterior teeth of this species differ exceedingly in 

 shape; the former are flattened, sharp-edged, and slightly incurved; 

 the edges not serrate. Those of the premaxillary bone are subequal in 



