170 
ZOOLOGY. 
come to the hake {Merhicius lilinearis), the haddock {Me- 
lanogranwins ^glcfiiius, Fig. 215), and cod {Gadiis morrlma 
Fig. 216), all of which extend northwards from Cape Hat- 
teras, the cod abounding on both sides of the Atlantic, 
being a circumpolar fish. The cod does not, as formerly- 
supposed, migrate along the coast, but seeks the cool tern 
perature to which it is adapted by gradually passing in the 
early summer from shallow to deep watei*, and returning as 
the season grows colder. It visits the shallow water of Mas- 
sachusetts Bay to spawn about the first of November, and 
towards the last of the month deposits its eggs. About 
eight or nine million of eggs are aniiuallv deposited by each 
Fig. 216.— The Cod-fish, Gadus morrhua. 
female. The eggs laid by the cod rise to the surface of the 
water, on which they float. The young fish hatch on the 
New England coast in twenty days after they are extruded. 
The cod is the most impor(^ant of all the food-fishes, 
whether we consider the number taken or the amount of 
capital involved in the cod-fishery. It abounds most on 
the Grand Banks of Newfoundland. The breeding habits 
of the haddock, hake, and pollock are probably like those 
of the cod. 
Fierasfer is a small eel-like fish, with a long, thin tail. 
It is typical of a peculiar family, and is noteworthy from 
being a " commensal" or boarder in the digestive canal of 
