330 FISHES OF ILLINOIS 



Order AWACANTHINI 



(the cod-like fishes) 



Skeleton bony; vertebrae numerous, the anterior simple; no spines in 

 any of the fins; ventrals jugular, below or in front of the pectorals; tail 

 isocercal (i. e., the vertebras in a right line and becoming progressively 

 smaller backward); pectoral arch suspended from the skull; no meso- 

 coracoid; scapular foramen nearly always between the hypercoracoid 

 and the hypocoracoid, and not in the hypercoracoid as typical in Acan- 

 thopteri; air-bladder without open duct. 



A large group, confined mostly to the cold depths of the ocean 

 and to the northern seas ; a few fresh water representatives. Many 

 of the marine species are among our most important food fishes. 



Family GADIDjE 



(the codfishes) 



Body more or less elongate; tail tapering, coniform; scales small, 

 cycloid; skeleton osseous; vertebras numerous; ventrals jugular, the pel- 

 vic bones loosely attached to the clavicular symphysis by ligament; 

 dorsal fin extending almost length of back, forming 1, 2, or 3 fins; anal 

 long, single or divided; caudal distinct or confluent with dorsal and anal; 

 no spines in any of the fins, all the rays being articulated; no mesocora- 

 eoid; hypercoracoid without foramen; gills 4, a slit behind the fourth; 

 gill-membranes separated or somewhat united, commonly free from the 

 isthmus; no pseudobranchias ; posterior edge of preopercle usually cov- 

 ered by skin; mouth large, terminal; chin with a barbel; pyloric caeca usu- 

 ally numerous, sometimes few or none; vent submedian; air-bladder gen- 

 erally well developed. 



The cods inhabit chiefly the seas of northern regions; a single 

 genus confined to fresh waters. Genera about 25; species about 

 140. Many of the species are of great value as food fishes. 



Genus LOTA (Cuvier) Oken 



(burbots) 



Body long and low, compressed behind; head depressed; anterior nos- 

 trils each with a small barbel ; chin with a long barbel ; gill-openings wide, 

 the membranes free from the isthmus; each jaw with broad bands of 



