NO. 2125. FISIIE.^ FROM THE OULF OF CALIFORNIA— SNYDER. 581 



tliesG peculiarities are characteristic of other Colorado forms. An 

 unusually narrow caudal peduncle distinguishes 0. latipinnis and 

 G. elegans, the depressed head is found in Ptychocheilus lucius, G. 

 rohusta, and X. texanus, and the dorsal crest is conspicuous in X. 

 texanus and G. rohusta. These characters become fully developed 

 only in old individuals. 



Gila River at Gila City; Colorado River, Yuma; Sal ton River, 

 Colorado Desert, Lower California. 



GILA ROBUSTA Cope. 



In large individuals the back is greatly arched, the head flattened, 

 and concave in outline. The maxillary appears longer, the tip ex- 

 tending beyond anterior margin of eye, which it does not reach in 

 small specimens. 



G. seminuda ^ seems to be synonymous with this species. In the 

 ventral region the scales are small, thin, and not securely embedded. 

 The observations of Ellis,^ "Specimens of this subspecies differ 

 from the typical G. rohusta in having no scales in the midventral 

 portion of the body as far posterior as the base of the ventrals and 

 no scales on the mid-dorsal region as far back as the middle or last 

 ray of the dorsal fin," are not applicable to this form, as the cotypes 

 of G. seminuda from the Rio Virgen have the entire ventral surface 

 scaled, where the scales have not been displaced by accident, in 

 which case the pockets remain. ' The same is also true of the mid- 

 dorsal region. 



Fishes of this species may be caught with baited hook, "the flesh 

 of a bird or minnows of its own species answering equally well. The 

 stomach of one specimen contained a frog." 



An example measuring 9^ inches from the Verde was colored in 

 life as f oUows : 



Dorsal aspect dark, dotted with gold and silver; sides with obsolete blackish bands, 

 most distinct toward the tail; below, silvery white; iris, golden; peritoneum, black. 

 A smaller specimen was lighter colored and had a gold band extending from the 

 superior extremity of the opercular opening to the base of the tail. In many speci- 

 mens the ventral siu-face ranges in color from pure white to rosy salmon. 



The species is locally known as bony-tail or Verde trout, and when taken from cool 

 water the flesh has an excellent flavor. 



Verde River at Fort Verde; Gila River at Gila City. 



PTYCHOCHEILUS LUCIUS Glrard. 



Colorado River at Yuma; Gila River. 



RICHARDSONIUS GIBBOSUS (Baird and Girard). 



In determining the identity of specimens collected by Doctor 

 Mcarns it became necessary to examine the types of Gila gihhosa 



1 Wheeler's Explor West of the 100th Merid., vol. 5, 1875 (1876), p. 666, pi. 31, figs. 1, la. 



2 Fishes of Colorado, Univ. of Colorado Studies, 1914, p. 57, Oila rohusta seminuda. 



