178 



O. C. Marsh — Miocene Art 'unhid i/lcs, > tr. 



Octacodon. valens. 



In addition to the two genera above described, there is a 

 third, closely allied to them apparently, which is now known 

 from various remains found in the same horizon. These re- 

 mains may for the present be provisionally placed in the genus 

 Octacodon^ a typical upper molar of which is shown below, 

 figure 6. One character seen in the teeth of this genus is the 

 short crowns of the premolars and molars and the low cusps and 

 cones of which they are composed. This feature will at once 

 distinguish the teeth from those known as Ryopotamus* 

 found in the same region. In the latter forms, the elevations 

 of the crowns are especially prominent and pointed, as shown 

 in the molar represented in figure 7. 



Figure 6. — Last right upper molar of Octacodon valens. Marsh; seeu from below. 

 Figure 7.— The same tooth of Ancodus (Hyopotamus) deftectus. Marsh. 

 Both figures are natural size. 



The position of the first premolar is another character of im- 

 portance. In Ileptacodon and Elomeryx, this tooth is situated 

 close to the second premolar, but in the specimens here referred 

 to the present genus, it is separated from both the canine and 

 the second premolar by a well-marked diastema. None of these 

 genera have the dependent process on the lower jaw which is 

 characteristic of Anthracotherium. The nearer relations of 

 these various allied forms will be discussed by the writer in i 

 later communication. 



Tale University Museum, New Haven, Coun., July 19, 1S94. 



* The generic name Ancodus, Pomel, has priority over Hyopotamus, Owen, and 

 the latter must be regarded as a synonym. The name of the family therefore 

 should be Ancodontidce. 



