A NEW FOSSIL STICKLEBACK FISH FROM NEVADA. 



By Oliver P. Hay, 



Of the American Museum of Natural Hldonj, Xew )o/-/.' cili/. 



The writer has received from the Geological Department of the 

 U. S. National Museum for description four specimens of small fossil 

 sticklebacks that were collected by Mr. Thomas H. Means from the 

 Lahontan beds, through which the Truckee irrigation canal was being 

 cut, three miles southwest of Hazen, Nevada. These fishes are 

 inclosed in a very white clay which splits readil}^ into thin lamina?. 



All the specimens belong to a single species, and this is a member 

 of the genus GastercMteus, a genus containing a number of small 

 spiny-rayed fishes known as sticklebacks. These inhabit the salt and 

 brackish waters of the coasts, as well as some of the fresh-waters, of 

 Europe and North America. One species, G. cataphraeius, is found 

 along the Pacific coast from San Francisco to Alaska. Another, G. 

 wHlfainson!^ occupies fresh-water streams in the interior of southern 

 California. A subspecies of this form, G. williamsoni mic7'ocephalus^ 

 inhabits streams and brackish waters along the coast from Alaska to 

 Lower California. 



The facts regarding the sticklebacks of the Pacific region are 

 obtained from Jordan and Evermann's Fishes of North and Middle 

 America. 



The fishes sent me are closeh' related to all the species just men- 

 tioned; also to G. hispinosus^ of eastern America, and to G. acideatvfi^ 

 of Europe. The fossils, however, present characters of subspecific 

 value. 



GASTEROSTE.US WILLIAMSONI LEPTOSOMUS, new subspecies. 



The first of the specimens (Cat. No. 5386, U.S.N.M.), the type, dis- 

 plays the nearly complete skeleton (fig. 1). Most of the important 

 bones of the head can be identified. The mouth gapes and displays 

 traces of teeth. The anterior dorsal spine is missing; the second and 

 third are represented by impressions in the clay. The dorsal soft rays 

 are disturbed and some are missing. The pectoral fin is preserved and 



Proceedings U. S. National Museum, Vol. XXXI|-No. 1528. 



271 



