I40 VERTEBRATE ANIMALS OF THE UNITED STATES 



spines below it; villiform teeth on the vomer, jaws and sometimes 

 the palatines; gill openings separated by a wide isthmus; pectoral 

 tins large; dorsal fins usually nearly or quite separate: numerous 

 species, in the northern hemisphere. 



Key to the Species of Cottus 



ai Palatine bones with teeth; the two dorsal fins usually very 

 slightly connected at base, or not at all. 

 bi Anal rays 15 to 20. 



Ci Vent midway between tip of snout and base of 



tail C. asper 



C2 Vent nearer the tail than the tip of the snout C. gulosus. 



b2 Anal rays 11 to 13. 



Ci In the far-western States. 



di Snout pointed . . .C. rhotheiis. 



d2 Snout blunt. 



Ci Caudal peduncle very slender C. pimctidatus . 



€2 Caudal peduncle deep (dorso-ventrally wide) C. semiscaber. 



C2 In the eastern and northern States C. ictalops. 



a2 Palatine bones without teeth. 



bi In the Klamath Lakes region, Oregon C. klamathensis. 



bo In the Columbia River basin C. heldingi. 



b.-j In the Colorado River basin C. annce. 



C. asper Richardson. Length 300 mm.; head 3.25; depth 4.5; 

 color grayish olive, mottled and spotted with blackish; prickles coarse 

 and stiff; rays of dorsal fins IX or X, 19 to 21; anal 17 or 18: San 

 Francisco Bay to Vancouver Island; abundant in cold streams. 



C. gulosus (Girard). Riffiefish. Length 150 mm.; head 3; depth 

 4.5; color grayish olive, mottled with darker; rays of dorsal fin VIII or 

 IX, 19 to 21; anal 16 to 18: southeastern Oregon; California, from San 

 Francisco Bay southward; very common. 



C. rhotheus Rosa Smith. Length 100 mm.; head 3; depth 4.5; color 

 dark gray, spotted and mottled; rays of dorsal fins VII or VIII, 16 or 17; 

 anal 11 or 12: Columbia River basin; common. 



C. punctulatus (Gill). Length 125 mm.; head 3; depth 4.75; color 

 olivaceous, spotted with black and with 5 or 6 dark lateral cross bars; 

 rays of dorsal fins VII or VIII, 17 or 18; anal 11 or 12: head waters of 

 Green River, Wyoming; southeastern Oregon; common. 



C. semiscaber (Cope). Rocky Mountain bullhead. Length 100 

 mm.; head 3; depth 4.5; color gray, with inconspicuous cross bars on the 

 sides; rays of dorsal fins VIII, 17 or 18; anal 12 or 13 : New Mexico and 

 Wyoming into Montana and Washington; common. 



