The Alewives 



It very closely resembles the European sardine ( Cliipanodon 

 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 RAFINESOUE 

 The Alewives 



This genus is very close to Cliipea 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 ; chrvsochloris, lo'i 



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 4I in length; 



psendoharengus, 103 

 bb. Peritoneum black ; cestivalis, 104 



Fresh-water Skipjack ; Blue Herring- 



Pomolobus cJtrysochloris 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 JVlichigan. 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 is inches, rarely takes the hook, and 

 is of very little value as a food-fish. 



Head j\\ depth 3J; eye 4I; D. 16; A. 18; scales 32; vent- 

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

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



