ARTIFICIAL KEY TO THE FAMILIES OF AMERICAN 

 FOOD AND GAME FISHES 



The following key is intended simply to facilitate the identification of the 

 species of American fishes which are used as food or which are sought by the 

 angler. No attempt is made to indicate the natural characters or relations of 

 the families, and only those species of any group which are included in the pres- 

 ent work are taken into consideration. 



I. VENTRAL FINS PRESENT, ABDOMINAL 



A. Back with an adipose fin behind the single rayed dorsal fin. 



B. Head with 4 to 8 long barbels about the mouth and nostrils; body scale- 



less; a single spine in each pectoral and in the dorsal fin. 



Ill, SiLURiD-iE, 15 

 BB. Head without barbels as described above. 



C. Dorsal, anal, and ventrals each with a small, but distinct spine; scales 



ctenoid XXIV, PERCOPSID^;, 247 



CC. Dorsal, anal, and ventrals without spines. 



D. Dorsal fin long and high, of about 24 rays XVI, THYMALLID/E, 220 



DD. Dorsal fin moderate, of fewer than 20 rays. 



E. Stomach with many pyloric cceca XV, SALMONID^E, 1 16 



EE. Stomach with few pyloric cceca; size small XVII, ARGENTINID^E, 225 



A A. Back without adipose fin. 



B. Back with a single dorsal fin made up of rays and not preceded by a 



series of free spines or followed by finlets. 



C. Tail evidently strongly heterocercal. 



D. Body naked; snout with a spatulate blade; mouth wide, without barbels. 



I, POLYODONTIDvE, I 



DD. Body with 5 series of body shields; mouth inferior toothless, preceded 



by 4 barbels II, ACIPENSERID^E, 4 



CC. Tail not evidently heterocercal. 



E. Pectoral fins inserted high, near axis of body; lower pharyngeals united; 



lateral line along sides of belly. 



F. Jaws each with long sharp teeth mixed with smaller ones. 



XX, BELONID^E, 241 

 FF. Jaws with small equal teeth, conic or tricuspid. 



G. Lower jaw more or less produced; teeth tricuspid. 



XXI, HEMIRAMPHID^E, 242 

 GG. Lower jaw a little produced; teeth conic; pectorals elongate, forming an 



organ of flight XXII, EXOCCETID^E, 243 



EE. Pectoral fins inserted below axis of body; lower pharyngeals separate. 

 H. Gill-membranes broadly joined to the isthmus; head naked; no teeth in 



jaws. 

 /. Lower pharyngeal teeth very numerous, in i row like the teeth of a comb. 



(Suckers.) IV, CATOSTOMID^;, 36 



//. Lower pharyngeal teeth few, fewer than 8, in i to 3 rows. (Carp; 



Chubs; Minnows.) V, CYPRINID^E, 67 



HH. Gill-membranes free from the isthmus. 

 K. Head scaly, more or less. 

 L. Teeth cardiform; jaws depressed, prolonged. .. .XIX, ESOCID^;, 233 



LL. Teeth villiform; jaws short; no lateral line XVIII, DALLIID^E, 232 



KK. Head naked. 



M. Gular plate present IX, ELOPID^E. 84 



MM. Gular plate none 



54i 



