219 



lliruiigli whose iulerch;! ia natural history most of the Oregon fossils have been 

 brought to the notice of the world. 



Perissodactyla. 



LOPHIODON? 



Among the fossils from Bridge Creek, in the Condon collection, there is a 

 small fragment of an upper jaw containing two molar teeth, represented in 

 Fig. 1, Plate II, which proljably indicates a tapiroid animal, allied if not 

 actually pertaining to the extinct genus Lophiodon. The teeth, which appear 

 to be the upper back premolars, are much worn, and the last one is mutilated. 

 They belonged to an animal about the size of the common American tapir, 

 ( Tapirus terrestris.) 



The teeth neai'ly resemble the corresponding ones, as we might suppose 

 them to 1)6 in the same state of wear, of Lophiodon isselense, of the Eocene 

 formation of France, as represented in Gervais's Plate XVIII, of the Zoologie 

 et Paleontologie francaises ; or they would appear to bear a nearer resem- 

 blance to those (A PalcRosyops paludosus of the Bridger Tertiary formation of 

 Wyoming. 



The teeth are inserted with three fangs, two externally and a broader one 

 internally. The crowns are widest transversely, square without, semicircular 

 within. They are composed of a pair of pyramidal lobes externally and an 

 internal median conical lobe embraced by a thick basal ridge. The antero- 

 external lobe extends in a ridge to the fore part of the base of the inner lobe, 

 and the postero-external lobe appears to have been continuous by a ridge 

 with the base of the inner lobe. A thin basal ridge festoons the outer part 

 of the crown. 



In the worn condition of the teeth they present a wide tract of dentine 

 continuously on the outer lobes. In the penultimate premolar the tract ex- 

 tends inwardly from the postero-external lobe on the inner lobe, and from 

 the antero-external lobe to the base of the latter in front. In the last pre- 

 molar the dentinal surface of the outer lobes extends continuously on the 

 inner lobe. 



The penultimate premolar measures 8J lines antero-posteriorly, and \\\ 

 lines transversely; the last premolar measured about 10 hues antero-poste- 

 riorly, 11 lines traoisversely. 



The size of the specimen, and its apparent rclatiiniship with Lophiodon, 



