146 University of Washington Publications in Biology [Vol. 2. 



3a. More than 100 scales along the lateral line ; a barbel terminal on pos- 

 terior tip of maxillary. Range : Introduced into the Columbia River 

 system, Puget Sound drainage and Vancouver Island. Freshwater. 

 Abundant. 

 Tench. Green Tench. Yellow Tench 78. Tinea tinea (Linnaeus) 



3b. Fewer than 100 scales along the lateral line. 



4a. A single row of pharyngeal teeth, the lesser row never developed. 



5a. Lower jaw with a conspicuous, broad, straight-edged, horny plate; 

 alimentary canal at least twice the length of body, with more than 

 1 main loop ; teeth usually 4-5, seldom 5-5, hooked and short ; per- 

 itoneum jet black; young with a black spot at the base of the cau- 

 dal fin rays in the mid-line. Range : Lower Columbia River sys- 

 tem, and Malheur Lake drainage, Oregon. Freshwater. Common. 



Chiselmouth. Square Mouth 



79. Acrocheilus alutaccus Agassiz and Pickering 



5b. Jaws without straight edged horny plate as above ; alimentary canal 

 about equal to or shorter than length of body, with but a single 

 main loop. 



6a. Scales with radii on all fields appearing like the spokes of a 

 wheel; 8 to 9 (usually 9) short blunt gill rakers on first gill 

 arch ; origin of dorsal fin posterior to base of pelvic fins ; head 

 about 4.7; depth 4.7; eye in head 4.6; scales 12 to 15+54 to 61 

 +8 ; dorsal 8, anal 7 ; scales before dorsal 32 to 38 ; pharyngeal 

 teeth usually 4 on right side and 5 on the left; peritoneum black 

 to dusky. Range : Streams tributary to the north end of Goose 

 Lake. Freshwater. Common. 

 Northern Roach 80. Hcsperoleucns mitrulus Snyder 



6b. Scales without radii in all fields, if radii are present ; 13 to 20 

 gill rakers on first arch, not very blunt ; origin of dorsal fin 

 above base of pelvic fins ; peritoneum dusky to white ventrally ; 

 (the species of Siphateles usually recognized are not clearly dif- 

 ferentiated except by drainage systems ; the differences when 

 studied statistically are probably significant). 



7a. Individuals inhabiting the Columbia River and Malheur Lake 

 drainage; scales 11 to 13 (11.6) +41 to 53 (46) +5 to 7 (6) ; 

 scales before the dorsal 24 to 29 (26); anal 8 to 9 (8.2). 

 Freshwater. Common. 



Roach of the Columbia River System 



81. Siphateles bicolor columbianns (Snyder) 



7b. Individuals inhabiting the Klamath River and Klamath Lakes 

 drainage systems; scales 10 to 12 (10.6) +43 to 53 (48) +5 

 to 7 (6.2) ; scales before the dorsal 22 to 27 (25) ; anal 7 to 

 8 (7.7). Freshwater. Common. 



Roach of the Klamath System 



82. Siphateles bicolor bicolor (Girard) 



7c. Individuals inhabiting the Sacramento-San Joaquin system, 

 Goose Lake and tributaries; scales 10 to 13 (11.0) +44 to 54 

 (49) +5 to 7 (5.8) ; scales before the dorsal fin 22 to 28 (25) ; 

 anal 7 to 9 (8.4). Freshwater. Common. 



Roach of the Sacramento System 



83. Siphateles bicolor fornwsus (Girard) 



