ON THE 



FL A.C3- OlFTEIR/IIsr JEJ 



AND THE 



ICHTHYOLOGY OF UTAH. 



BY EDWARD D. COPE, A.M. 



The observations recorded below are based on the collections made by 

 the naturalists attached to the United States Geological and Topographical 

 Survey west of the 100th meridian, under direction of Lieutenant Geo. 

 M. Wheeler, and are published by permission of that officer. To Dr. 

 Henry C . Yarrow, in charge of the department of zoology, and to A. W. 

 Henshaw, assistant, the survey is indebted for material more fully 

 illustrating the character and distribution of 'the cold blooded vertebrata 

 of the valleys of the Colorado River and of Utah than any heretofore 

 brought together. As one of the results derived from a study of it, it 

 appears that the basin of the Colorado River is the habitat of a small 

 group of fishes of the family Cyprinidse, which may be called the Plagop- 

 terince, which embraces three genera Plagopteriis, Cope; Lepidomeda, 

 Cope; and Meda, Girard. The group differs from others of the family in 

 the possession of two strong osseous rays of the dorsal fin, the posterior 

 of which is let into a groove in the hinder face of the anterior without 

 being coossified with it, thus constituting a compound defensive spine. 

 The rays of the ventral fin, excepting the first and second, are similarly 

 modified. The greater part of their length consists of ari osseous dagger- 

 shaped spine, with grooved posterior edge, which overlaps the border of 

 the succeeding ray, when the fin, like a fan, is closed up. The articulated 

 portion of the ray either emerges from the groove below the free acute 

 apex of the spine, or appears as a continuation of the apex itself. It is 

 worth observing that the only other instance of this ossification of the 

 ventral rays is to be seen in the extinct family of the Saurodontidm of the 

 cretaceous period, the nearest approach among recent fishes being the 

 internal spine in the ventral fin of Amphacanthus. The dentition and 

 intestine of these fishes show them to be of carnivorous habits. Interest 



