1883.] NATURAL SCIENCES OF PHILADELPHIA. 161 



COBITIDJE. 



A species of this family left remains in the Idaho Lake basin. 

 I have reached this conclusion by the discovery, among the speci- 

 mens submitted to me hy the Smithsonian Institution, of the 

 inferior element of the three modified anterior vertebrae,^ which 

 are so characteristic of certain families of the Physostomous 

 fishes. This portion, moreover, is that which occupies the posi- 

 tion among the Cobitidse only. Among them, it consists of a 

 longitudinal plate terminating posteriorly in a bladder-like chamber 

 on each side, each of which is closed below by a transverse pro- 

 cess of the inferior plate ; an angular fissure extends around the 

 ends of these, and at the angle sends a short continuation 

 upwards. This is quite similar to what is observed in Cohitis. 



This occurrence of Cobitidse is, perhaps, the most interesting 

 fact brought to light by the examination of these extinct fishes. 

 All of the numerous existing species of this family are found in 

 the Eastern Hemisphere, and the great majority in tropical Asia, 

 a few only occurring in Europe and South Africa. Extinct 

 species are found in the miocene of Oeningen. We have then, in 

 this form, another example of the occurrence of Asiatic tj'pes in 

 North America prior to the glacial epoch ; and as in a fresh-water 

 fish, more strongly demonstrative of continuity of territory of 

 the two continents, than can be with any other type of animal. 



SALMONID^. 



EHABDOFAKIO Cope. 



Proceeds. Amer. Philosoph. Society, Nov., 1870. 



A genus represented by skulls, in which the maxillary bone is 

 cjdindrical and rod-like, thus differing from Salmo. 

 Rhabdofario lacustris Cope, 1. c. 



A species with a head as large as that of the Salmo mlar^ which 

 was not uncommon in the Idaho Lake. In addition to the type 

 obtained by Mr. King, Mr. Wortman found parts of several 

 intlividuals. 



SILURIDJE. 



AMIUEUS Raf. 

 ? Amiurus sp. 



Represented by pectoral spines. These do not diflTer from those 



of some recent species, but difler from those of the species of 



^ The pharyngeal bones referred to this family by me as above cited, 

 belong to the Cyprinidae in the restricted sense. See genus Diastichus. 



