Peterson: Material Discovered in Uinta Basin. 55 



portion of the maxillary apparently had considerable vertical diameter 

 and the zygomatic arch is rather slender. 



The general contour of the horizontal ramus of the type as well as 

 of the paratype is not unlike that of Oodectes. The diameter of the 

 jaw is small transversely and great vertically, with the lower border 

 suddenly rising opposite Mj and gradually tapering towards the 

 symphysis (see PI. XXXV, Figs. lo, 15). The latter is curiously sug- 

 gestive of Sinopa, having a shallow, quite long, and loose symphysis. 

 In fact the entire jaw is like that of the latter genus, but the canine is 

 heavier, the premolars set closer together, the cusps of all the teeth 

 lower, the heels of molars not basin-shaped, and M^j- too much reduced 

 (added to this the different structure of the limbs, vide infra) to permit 

 it to be regarded as belonging to Sinopa. 



There are two mental foramina of moderately large size, the ante- 

 rior under P2- and the posterior under the posterior portion of P^-. 

 In the type the base of the ascending ramus is very close to the dental 

 series, so that the posterior fang of M3- is placed at a considerable 

 angle to the position of the roots in the rest of the cheek-teeth. 

 This is not the case in the paratype, where there is a wider space 

 between M-g- and the ascending ramus. Whether or not this is a 

 specific character cannot be determined from the material at hand. 

 The ascending ramus of the rami of both type and paratype are broken 

 off. 



M EASUREMENTS. 



Type Paratype. 



No. 2928. No. 3006 



Transverse diameter of upper molar 12 mm. 



Antero-posterior diameter of upper molar 7 



" " " " horizontal ramus from incisor to 



and including M3 65 mm. 75 



Vertical diameter of ramus at Py 17 " 20 



" M^ 23 " 26 



Length of molar-premolar series 51 " 59 



" " premolar series 28 " 33* 



" molar series 25 " 26* 



Antero-posterior diameter of My 9-5 



" Mt 9 



Vertebral Column: The vertebral column of the paratype. No. 3006, 

 is represented by a few fragments of the centra, which present no 

 features worthy of mention, except that the caudal region was long 

 and robust, as usual in the Eocene Ferce. 



* Indicates the measurements to be approximately correct. 



