The measurements of the specimen are as follows: 



Lines. 



Greater diameter of the dermal bone , IG 



Shorter diameter of the dermal bone 15 



Thickness from summit 8 



The many more fossil-remains of fishes from the Tertiary formation of 

 Idaho, described by Professor Cope, he attributes to two additional species 

 of Mylocyprinus, seven species of four other genera of Cyprinidse, and a 

 species of Salmonidse. Fossil-shells described by Mr. Meek from the same 

 formation, as well as the cyprinoid fishes, indicate a fresh-water deposit. The 

 presence of a ray may probably indicate an easy communication with salt 

 water. 



34 G 



