GENERAL REMARKS ON FISH. 45 



rate, would be seventy-two millions. At an average of ten 

 pounds, these fish, of the third generation, would weigh seven 

 hundred and twenty million pounds, or enough to load three 

 hundred and twenty- two ships, of a thousand tons each. 



Some fish produce large ova, covered with horny shells. 

 Some few, including the true shark, are viviparous, producing 

 their young alive; the eggs, of course, being fecundated in 

 the abdomen ; but with all fish which contribute to the sport 

 of the angler, the female casts her roe, which is impregnated 

 by the milt of the male being cast over it. 



There are no hermaphrodites amongst fish, as has been 

 supposed by some ichthyologists, who cite the Lamprey as 

 one. It has been satisfactorily ascertained, that amongst all 

 the vertebrates, on land or in the water, there are no such ex- 

 ceptions. 



There are immutable laws in Grod's providence, which 

 compel the migration of fish as well as of birds. Some 

 species are anadromous, as the Salmon, Sea Trout, Smelt, 

 Shad, and Eiver Herring; these change their habitation 

 annually from the sea to fresh rivers, which they ascend 

 for the purpose of spawning ; most of them with wonderful 

 instinct returning, if there be no obstructions, to their native 

 streams, and in their course supply us with food, when in 

 their greatest physical perfection. After propagation, in 

 meagre, lank condition, they seek the sea again, where, from 

 the abundance and great nutritive quality of their food, they 

 recuperate and grow rapidly. The young fry that go seaward 

 diminutive in size, return the following spring or summer 

 adult fish, perfect in their powers of reproduction. 



Some of the species common to the long rivers and great 

 lakes of our interior, also change their abodes, traversing 

 perhaps as great an extent of water as the Shad and Salmon, 

 though not for the purpose of spawning. 



