FISHES 37 



A. alabamcB Jordan & Evermann. Length 375 mm.; head 4.6; 

 depth 3; color Hke A. sapidissima; rays of dorsal fin 15; anal 20; scales 

 55: streams entering the Gulf of Mexico. 



A. ohiensis Evermann. Length 375 mm.; head 4.5; depth 3.6; 

 body very long and slender and compressed; rays of dorsal fin 18; anal 

 18: Ohio River at Louisville; rare. 



Family 4. Salmonidae. — Whitefish; salmon; trout. Body elon- 

 gate, more or less elliptical, covered with cycloid scales; mouth terminal; 

 maxillary, with supplementary maxillary, forming the side of the upper 

 jaw; tail forked; pseudobranchiae present; no barbels; lateral line 

 present; air bladder large; pyloric caeca very numerous; posterior 

 dorsal fin adipose; tailfin forked: 10 genera and about 70 species, 

 grouped in 2 subfamilies, which live in the northern latitudes of the 

 New and Old World, mostly in fresh water; many of the marine 

 species ascend the streams to spawn; the family includes many of the 

 most important food and game fishes. 



Key to the Subfamilies of Salmonidae 



ai ]\Iouth small; upper jaw extending to the eye (Fig. 18) i. Coregonince. 



aj Mouth large; upper jaw extending back of the eye (Fig. 21) 2. Salmonince. 



Subfamily i. Coregoninae. — Mouth usually small; the maxillary 

 extending to a point in front of or beneath the anterior border of the 

 eye; dentition feeble; flesh white: 3 genera, i in Arctic America, in 

 lakes and rivers. 



Key to the Genera of Coregoninae in the United States 



ai Lower jaw shorter than the upper; premaxillaries broad, with the 



cutting edge vertical or directed backwards i. Coregonus. 



a2 Lower jaw usually longer than the upper; premaxillaries with the 



cutting edge horizontal or directed forwards 2. Lciicichthys. 



I. Coregonus L. Whitefish. Body elongate, compressed; head 

 small; mouth small; teeth minute or wanting; pseudobranchiae large; 

 air bladder very large: 18 species, in clear lakes in the northern hemi- 

 sphere, those in Arctic America descending to the sea; 6 species in the 

 United States. 



Key to the Species of Coregonus in the United States 



a I Species in the eastern and central States. 



bi Upper jaw reaching beyond the front margin of the eye. 

 Ci Body not tuberculated; in the Great Lakes and north- 

 wards C. clupeaformis. 



