Fishes of Massachusetts. 443 
mack, and the Concord shad were caught a month 
earlier than those of the Merrimack above its junc- 
tion with the Concord. The Concord shad have 
almost entirely disappeared, their ascent having been 
cut off by dams. 
The usual weight of this species is from one to 
four pounds, although it sometimes attains six 
pounds. Color upon the top of the head and the 
back, bluish ; the upper portion of the sides, includ- 
ing the opercula, cupreous; beneath silvery. Whole 
body covered with large, deciduous scales, with the 
exception of the head, which is naked. EH yes large; 
pupils black ; irides silvery ; the diameter of the eye 
equal to the distance between the eyes. Nostrils 
nearer the anterior angle of the eye than the snout. 
Upper jaw notched in its centre; its lateral edges 
slightly crenated. Length of the head to the whole 
length of the body as 1 to 6; the greatest depth of 
the body equal to nearly two thirds the length of the 
head; the width across the body, from the com- 
mencement of the dorsal fin to the anal, nearly one 
fifth the length of the fish. Abdominal ridge ser- 
rated throughout, from the inferior angle of the oper- 
culum to the anus; the serrations more prominent 
back of the ventrals. At the posterior angle of the 
operculum, a black blotch of considerable size ; in 
some specimens very indistinct until the scales are 
removed, when it is very obvious. 
The Dorsal fin, which shuts into a groove, is situ- 
ated on the middle of the dorsal ridge; the height of 
the first rays is equal to two thirds its length. 
The Pectorals silvery ; their length equal to about 
