Cope.] 5 7 [Jan. is, 



The skulls of this species came from the John Day bed of the John Day 

 river, Oregon, and were found by Mr. J. L. Wortman. The species was 

 established on an immature individual. The adults show that it belongs 

 to this genus. 



COLOREODON Cope. 



Proceedings American Philosophical Society, 1879, p. 375. 



Superior premolars three, the fourth with two external Vs, no facial va- 

 cuities. 



The mandibles of the species of this genus are unknown, so that the 

 character of the inferior dentition is unknown. The otic bullae are also 

 destroyed in all the specimens, so that their character is unknown. 



In its reduced dental formula this genus represents one stage of that 

 specialization which Owen has shown, has overtaken all the modern types 

 of Mammalia. In this series this process seems to have stopped at this 

 point, and not to have gone further, as the entire line has come to an end. 



The first superior premolar probably exists in a rudimental condition for 

 a short time, and is early shed. The same state of things has been found 

 to exist as an abnormality on one side in the Agriochoerus guyotianus, and 

 may be found again, but not so as to invalidate the characters of the genus 

 doloreodon. 



Two well-marked species of this genus have been described, which dif- 

 fer as follows : 



Smaller ; palatonareal border opposite posterior cusps of second 

 true molar ; sagittal crest anterior, commencing opposite 

 optic foramina C. ferox. 



Larger ; palatonareal border opposite posterior cusps of third 

 true molar ; sagittal crest posterior, commencing opposite 

 preglenoid border O. macrocephalus. 



Coloreodon ferox Cope. Fig. 1, p. 505. 



Proceedings American Philosophical Society, 1879, p. 375. 

 The size of Oreodon culbertsoni. Known from one skull from the North 

 Fork of the John Day river, Oregon. C. H. Sternberg. 



Coloreodon macroceplialus Cope. 



Proceedings American Philosophical Society, 1879, p. 376. 



Size of the Eucrotaplms major. The typical skull is from the North 

 Fork of the John Day river. A second skull, lacking all the parts posterior 

 to the anterior origin of the sagittal crest, is undistinguishable from the 

 first. It was found at the " Cove " of the John Day river, Oregon. Both 

 were obtained by Mr. J. L. Wortman. 



