The Alewives 



It very closely resembles the European sardine (Clupanodon 

 pilchardus), but is distinguished by the absence of radiating 

 striae on the opercles. From the California sardine it is distin- 

 guished by the smooth opercles, unspotted sides, and the pres- 

 ence of minute teeth on tongue and lower jaw. 



GENUS POMOLOBUS RAFINESQUE 

 The Alewives 



This genus is very close to Clupea from which it seems to 

 differ only in having no teeth on the vomer. 



As here understood this genus contains 4 known species, 

 each of some value as food. 



a. Teeth present in the jaws, those on tip of each jaw mostly 



persistent; chrysochloris, 101 



aa. Teeth in jaws disappearing with age. 



b. Peritoneum pale. 



c. Head long, about 4 in length ; mediocris, 102 



cc. Head shorter and heavier, about 4! in length; 



pseudoharengus, 103 

 bb. Peritoneum black ; cestivalis, 104 



Fresh-water Skipjack ; Blue Herring 



Pomolobus cJirysockloris Rafinesque 



This species is found in all the larger streams of the Mis- 

 sissippi Valley and has been introduced through canals into Lakes 

 Erie and Michigan. As ordinarily seen it is strictly a fresh-water 

 fish, but along the Gulf coast it enters salt water where examples 

 of large size and excessive fatness are occasionally taken. In 

 Lake Erie it is called "sawbelly," from the ventral scutes. This 

 species reaches a length of 15 inches, rarely takes the hook, and 

 is of very little value as a food-fish. 



Head jjf; depth 3f; eye 4^; D. 16; A. 18; scales 52; vent- 

 ral scutes 20+13. Body elliptical, much compressed; head rather 

 slender and pointed, its upper profile straight; lower jaw strongly 



