ISOSPONDYLI. 67 



The recurved plate of the base is rugose as in other catfishes. The 

 spines themselves are less compressed than in B. calvus. 



It is probable that the name applied by Dr. Leidy to this species was 

 published a short time before my own, but as it was not accompanied by a 

 description it cannot be used. 



From the Bridger beds of the Upper Green River. 



? Rhineastes radulus Cope. 



Annual Report U. S. Geol. Siirv. Terrs., 1372 (1873), p. 639. 

 Plate V, figs. 14-17. 



This species rests on a number of broken cranial bones. I referred it 

 fonnerly to this genus, but now regard the reference as purely provisional. 

 It is likely that it does not belong to BJiineastes, but what its proper generic 

 position is, I am not at present able to determine. 



The cranial bones pi'esent a pattern of exostosis quite distinct from 

 that observed in the known species of Rhineastes. This consists of closely 

 placed crenate ridges, which radiate from various points, and are sometimes 

 broken up, but always rough or serrate on the edges. The bones are not 

 so thick as in the R. peltatus; i. e., .0025 m. - ' 



From bad lands of Cottonwood Creek, Wyoming. 



ISOSPONDYLI. 



Cope, Proceedings American Association for the Advancement of Science, 1871, p. 33. 



Actinopterous fishes with physostomous characters, having the scapular 

 arch suspended to the cranium; a praecoracoid arch, and a symplectic bone, 

 but no coronoid bone, and with the anterior vertebrae unmodified and with- 

 out ossicula auditus. 



Two families of this order are represented in the Green River and 

 Bridger beds by numerous individuals. These are the OsteoglossideB and 

 the Clupeidce, which are distinguished by the following characters of the 

 skeleton : 



Tail, homocercal; pterotic bone, normal; basis cranii, double; superior 

 pharyngeals four, distinct, third largest and directed forwards; basal bran- 

 chihyals three; parietals separated by supraoccipital; one vertebra included 



