KEY TO THE FAMILIES OF ILLINOIS FISHES 3 



u. Ventral rays usually I, 7 (I, 6 or 7) ; vent in front of pectorals 



Aphredoderidae. Page 228. 



uu. Ventral rays I, 3 to I, 5, typically I, 5; vent normal. 

 V. Chin without barbel, 

 w. Body scaled. 

 X. Anal spines 3 to 10. 



y. Lateral line wanting Elassomidae. Page 231. 



yy. Lateral line present. 

 z. Dorsal fins confluent, the spinous portion always somewhat lower than the 



soft portion; in forms with deep notch between dorsal fins, the highest 



dorsal spine but little more than half the height of the highest soft ray. 



Centrarchidae. Page 232. 



zz. Dorsal fins either (1) separate, and the soft and spinous portions about 

 equally high; or (2) barely confluent, with the notch between them very 

 deep and with the highest dorsal spine as high as, or higher than, the 

 highest soft ray (marine forms not included) Serranidae. Page 318. 



XX. Anal spines 1 or 2, never more than 2. 



z'. Lateral line not extending on rays of caudal fin Percidae. Page 269. 



z'z'. Lateral line extending on rays of caudal fin Sciaenidae. Page 322. 



WW. Body naked, or variously armed with scales, prickles, or bony plates, 

 never uniformly scaled Cottidae. Page 325. 



vv. Chin with a median barbel Gadidae. Page 329. 



