Fishes of Massachusetts. 535 
In the summer, this is quite a common species in 
our waters. The fishermen, while fishing for mack- 
erel and cod, are frequently much annoyed by hav- 
ing their hooks and lines bitten off by this intruder. 
It occasionally attains the length of eight or nine 
feet, and weighs between 300 and 400 pounds. No 
portion of it is used save the liver ; this organ, how- 
ever, furnishes a valuable oil. Seven gallons of oil 
are not unfrequently extracted from the liver, of a. 
single fish. And although it is generally used only 
by the curriers, yet, when carefully prepared by 
boiling the fresh liver, it is as good as whale oil to 
burn. As this species is generally seen following 
shoals of mackerel, upon which it feeds, it is com- 
monly known among the fishermen as the Mackerel 
Shark. 
By the politeness of ` Messrs. McLoud and Dill, 
fishmongers, I was enabled to examine a fine speci- 
men of this species, eight feet in length, taken the 
latter part of July, 1838, in a net at Marshfield ; from 
this specimen, I drew up the following account : 
All the upper part of the body, greenish ; lighter 
upon the sides ; white, beneath. Head, small; snout 
blunted at its tip. Eyes circular, very moveable in 
their orbit; pupils black; irides dusky; diameter 
of the eye, two inches; distance between the eyes, 
five inches. Nostrils large, situated vertically under 
the snout. On a line above the eyes, a series of mu- 
cous pores resembling black orifices, are seen run- 
ning towards the snout; another series, between the 
eyes, (on a line with them,) and the snout. Upon the 
whole under portion of the snout, these are also 
