36 VERTEBRATE ANIMALS OF THE UNITED STATES 



the distance to the tail; rays of anal fin 31; scales 56-23; stomach 

 like a fowl's gizzard: Cape Cod to Mexico, in the sea and ascending 

 the rivers; Mississippi Valley; introduced into Lakes Erie and Michigan 

 and in ponds from New Jersey to Texas; common; of little food value. 

 Family 3. Clupeidae. — Herring; shad. Body oblong or elongate, 

 covered with cycloid scales; mouth large and terminal; teeth feeble 

 or wanting; maxillaries formed of 2 or 3 pieces and forming side of 

 upper jaw; pseudobranchiae 6 to 15; no lateral line; branchiostegals 

 6 to 15; tail forked: about 30 genera and 150 species, mostly marine, 

 inhabiting all seas ; a few species live in fresh water and several marine 

 ones enter streams to spawn. A number of marine species, such as 

 the common herring, Clupea harengus L., the alewife, Pomolohus 

 pseudoharengus (Wilson), the shad, Alosa sapidissima (Wil.), the 

 European sardine Clupanodon pilchardus (Walbaum) and the men- 

 haden, Brevoortia tyrannus (Latrobe), swim in large, often immense, 

 schools, and are very important food fish. 



Key to the Fresh Water Genera of Clupeidae 



ai Jaws with teeth i. Pomolohus. 



a2 Jaws toothless 2. Alosa. 



1. Pomolobus Rafinesque. Body elliptical, compressed; scales 

 cycloid; teeth feeble: many species, mostly in northern seas. 



P. chrysochloris Raf. Skipjack. Length 375 mm.; head 3.75; depth 

 3.75; color brilliant blue above; sides silvery, with golden reflections; 

 rays of dorsal fin 16; anal 18; scales 52; lower jaw projecting: Mis- 

 sissippi Valley and Gulf of Mexico; common in the larger streams; 

 introduced into Lake Erie and Michigan; of no food value. 



P. pseudoharengus (Wilson). Alewife. Length 375 mm.; head 4.6; 

 depth 3.3; color bluish above, with silvery sides; a small black spot 

 behind the opercle; rays of dorsal fin 16; anal 19; scales 50: Atlantic 

 Ocean, south to South Carolina, entering the streams to spawn; in 

 Lake Ontario and the lakes of central New York; very common. 



2. Alosa Cuvier. Body elliptical, compressed; jaws toothless; upper 

 jaw with a deep notch at the tip: 3 American species. 



A. sapidissima (Wilson). Shad. Length 750 mm.; head 4.25; 

 depth 3 ; color bluish above; sides silvery; a dark spot, or a row of several, 

 behind the opercle; gill-rakers 60, very long and slender; rays of dorsal 

 fin 15; anal 21; scales 60: Atlantic Ocean, Newfoundland to the Gulf 

 of Mexico, ascending the streams to spawn; common; introduced into 

 the Pacific Ocean, and very common from San Diego to Fort Wrangel ; 

 the most valuable food fish in the eastern States. 



