FISHES 35 



Key to the Species of Hiodon 



ai Dorsal fin with 9 rays H. alosoides. 



ao Dorsal fin with 12 rays. 



bi In the north-central States H. iergisus. 



bo In the southeastern States H. sclenops. 



H. alosoides. (Rafinesque) . Mooneye. Length 300 mm.; head 

 4.5; depth 3.5; color bluish; sides silvery, with a golden lustre; rays 

 of dorsal fin 9; anal 32; scales 6-56-7; belly in front of ventrals cari- 

 nated: Ohio River basin and Great Lakes region to the Saskatchewan; 

 common northwards. 



H. tergisus LeSueur (Fig. 17). Mooneye; silver bass. Length 

 300 mm.; head 4.3; depth 3; color olivaceous with silvery sides; rays 

 of dorsal fin 12; anal 28; scales 5-55-7; belly behind ventrals somewhat 



Fig. 17. — Hiodon tergisus (Jordan b" Evermann). 



carinated: basin of the Ohio River; Lake Erie to the Lake of the Woods 

 and Montana; common in large streams. 



H. selenops Jordan & Bean. Body elongate; length 300 mm.; 

 head 4.1; depth 4; color clear silvery; rays of dorsal fin 12; anal 27; 

 scales 50: Tennessee, Cumberland and Alabama Rivers; rare. 



Family 2. Dorosomidse. — Body short and deep, strongly com- 

 pressed; scales cycloid; belly carinated; no lateral line; mouth toothless, 

 small; branchiostegals 6; pseudobranchioe large; eyelid adipose; anal 

 fin very long and low ; tail forked : i genus. 



Dorosoma Rafinesque. With the characters of the family; 10 

 species of mud-feeding fishes, in warm seas and rivers; i in the United 

 States. 



D. cepedianum (LeSueur). Gizzard shad; mud shad. Length 

 375 mm.; head 4.3; depth 2.5; color silvery, being bluish above; rays 

 of dorsal fin 12, its posterior ray very long and extending back half 



