OF FISHES. 59 



after the lights have been extinguished. This is 

 inferred from their remaining precisely in one posi- 

 tion, six and eight hours at a time. 



PROCREATION. 



Fishes are astonishingly prolific : — a majority are 

 oviperous, and some of the condropterygii are vi- 

 viperous. This latter class, however, are less nu- 

 merous than the first. It has been often asserted 

 by credible writers, that the cod produces nine mil- 

 lion of eggs in a season ; — the common flounder a 

 million, and the mackerel, above five hundred 

 thousand. On the other hand, the cartilaginous 

 varieties seldom give birth to more than a few 

 hundreds of living young at a time. If only one 

 in the three hundred arrives at maturity, its power 

 will ensure the continuance of the race, but with 

 the social and andromous, scarcely ten eggs in a 

 thousand are ever developed, — being the necessa- 

 ry aliment of others, — but the continuance of the 

 species is thus insured against all probable contin- 

 gencies. 



Each egg is filled with a yolk, surrounded by aF* 

 bumen, like that of the serpent, the crocodile, and 

 the bird. They are commonly extruded in shal- 

 low water, out of the reach of eddies, where by the 

 glutinous envelope in which the mass is held to- 



