FISHES 35 



Key to These Families 



ai Lateral line present i . Hiodontidce. 



a.2 Lateral line absent. 



bi Last rays of dorsal fin much elongated 2. Dorosomidcc. 



hi Dorsal fin normal 3. Clupeida. 



Family i. Hiodontidae. — The mooneyes. Body oblong, com- 

 pressed, covered with silvery cycloid scales, short; mouth terminal, 

 oblique; tail forked; branchiostegals 8 to 10; lateral line present; 

 teeth on jaws, margin of the tongue, vomer, sphenoid, hyoid, pterygoid 

 and palatines; eyes very large; no pseudobranchiae; i pyloric appendage: 

 2 genera. 



I. Hiodon LeSueur. Dorsal tin with 12 rays: 2 species, of httle 

 food value. 



Fig. 17. — Hiodon tergisus {Jordan <jf Evcrmann). 



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

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

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

 carinated: basin of the Mississippi River; Great Lakes; common in 

 large streams. 



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

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

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



2. Amphiodon Rafinesque. Dorsal fin with 9 rays: i species. 



A. 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 6-56-9; belly in front of ventrals cari- 

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

 common northwards. 



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

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



