532 THE WASATCH FAUNA. 



Specimens were collected by J. L. Wortman in the Big-Horn region, 

 Wyoming. 



CORYPHODON SIMUS CopC. 



Report Vert. Foss. New Mexico, U. S. Geogr. Surveys W. of 100th Mer., 1874, p. 8. Report U. S. 

 Geogr. Surveys W. of lOOtli Mer., 1877, iv, pt. ii, p. 225. PI. LV. 



A broken mandible and maxillary bone, with several teeth, represent 

 this small species in the Big-Horn collection. Maxillary teeth of similar 

 proportions were found by Russell S. Hill in the Eocene of Powder River, 

 Wyoming. 



CoRYPHODON REPANDUS Cope. 

 Paleontological Bulletin No. 34, p. 171, Feb. — , 1882. Proceed. Amer. Philos. Soc, 1881, p. 171 (1882). 



Plate XLIVe; figs. 1-4. 



This large species is known from the posterior portions of the dentition 

 of both jaws, with an entire symphysis. 



The last superior molars are intermediate in outline between the reg- 

 ular oval of the C. latipes and the subtriangular form of the C. elepJiantopiis. 

 The peculiarities of the species are seen in the posterior crest. The two 

 lobes of which this is composed do not form a continuous line as in C. 

 latipes and C. simm, but form an angle with each other as in C. anax. The 

 anterior lobe is compressed, and its long axis is nearly that of the jaw; the 

 second lobe leaves it at a right angle, but curves backwards as it extends 

 inwards, giving a concave exteroposterior border. There is no ridge de- 

 scending outwards from the inner extremity of the crest, to form a V, as in 

 C. elephantopus. But the posterior basal cingulum extends to the external 

 side of the tooth, which is not the case in any other species known to me 

 excepting the C. marginatus. The anterior cusp is closely joined to the 

 external elevation of the anterior first cingulum as in C. anax; a character 

 which separates it from all other species. A strong trace of a cingulum 

 passes round the inner base of the crown. No external cingulum. The 

 first true molar does not diifer materially from that of other species. It is 

 considerably smaller than the last. The apex of the premaxillary bone 

 with the second incisor and alveolus of the first is preserved. The bone 



