1936] Schults: Keys to Fishes 147 



7d. Individuals inhabiting the lakes of southeastern Oregon, name- 

 ly lakes Abert, Summer, Silver, Alkali, Warner, and their trib- 

 utaries ; scales 11 to 14 (12.2) +45 to 60(52)+6 to 9 (6.8); 

 scales before dorsal fin 24 to 33 (29); anal 7 to 11 (7.8). 

 Freshwater. Common. 



Roach of Southeastern Oregon Lakes 



84. Siphatclcs bicolor orcgonensis (Snyder) 



7e. Individuals inhabiting the lakes and streams of the Lahontan 

 Basin; scales 12 to 16+50 to 60 (usually 53 to 56) +7 to 8; 

 scales before the dorsal 27 to 33 (usually 29 to 31) ; gill rak- 

 ers 8 to 20 (usually 10 to 18) ; anal rays 7 to 8; dorsal 8. 

 Freshwater. Common. 



Roach of the Lahontan Basin 



85. Siphatclcs bicolor obesus (Girard) 



4b. Pharyngeal teeth present, in 2 rows, the lesser row occasionally 

 absent on one side. 



8a. Teeth in main row blunt, molar or stump shaped in adult, 

 but often slightly hooked in the young; the teeth never ta- 

 pering evenly to a hooked point as in 8b. 



9a. Premaxillary not protractile but bound to snout by a fre- 

 num ; no barbels on maxillary ; scales between occiput and 

 dorsal fin 45 to 55; (found only south of Oregon). Range: 

 Sacramento River system. Freshwater. Abundant. 



Hardhead. (Sacramento River system) 



86. Mylopharodon conoccphalus (Baird and Girard) 



9b. Premaxillary proctractile ; barbel present on maxillary ; 

 28 to 35 scales between occiput and dorsal fin ; peritoneum 

 dusky to black in very young; young without a jet black 

 spot at base of caudal fin rays as found in Ptychochcilus, 

 the spot in Mylochcilus at most is very pale. Range : 

 Drainage systems from the Columbia to the Fraser. 

 Freshwater. Common. 



Columbia River Chub 



87. Mylochcilus caurinus (Richardson) ° 



8b. Teeth in main row hooked and usually compressed, tapering 

 to a more or less hooked point ; never blunt and without 

 grinding surface. 



10a. A barbel on the posterior angle of maxillary, usually 

 small and seldom obsolete except on very young in- 

 dividuals. 



11a. Premaxillary protractile. 



12a. Between occiput and dorsal fin 16 scales ; 35 to 40 

 scales in the lateral line. Range : Willamette and 

 Umpqua rivers. Freshwater. Common. 



Oregon Chub or Minnow 



88. Oregonichthys crameri (Snyder) 



12b. Between occiput and dorsal fin 28 to 34 scales and 

 more than 43 scales in the lateral line. 



"Reasons for changing name see Hubbs and Schultz 1931, Occ. Pap. Mus. Zool. Univ. 

 Mich. No. 232: 1-6. 



