258 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



materially decreased in the course of centuries. This will easily be un- 

 derstood when we state the fact that a single herring produces 60,000 

 eggs, whilst the codfish matures as many as 2,000,000. It should also 

 be remembered that the young fry hatched from these eggs grows up 

 without any great difficulty. Young fish know how to take care of 

 themselves the moment they leave the egg, and father and mother need 

 not look after them. The work of the codfish would be truly enor- 

 mous if, like the birds, it had to feed its innumerable young. 



The sea is not only enormously rich in fish, but also in other animals. 

 In its depth there live and thrive a very large number of different kinds 

 of animals, all differing from each other in size and shape, and fre- 

 quently of such curious form that the limits of a brief lecture would not 

 suffice even to give a mere enumeration of them. We must, however, 

 devote a few words to the crustaceans, some kinds of which, like the 

 lobster, the shrimp, and the crab, are well known to every one, because 

 they form common articles of food. 



The crustaceans are a war-like race, encased in a coat of armor from 

 head to heel. This armor consist* of a thick, chalky skin, whose joints 

 are both strong and flexible. Besides this they are furnished with dif- 

 ferent weapons of attack. Some have shears, which in the larger kinds 

 may even prove dangerous to man ; others have a long and spear-like 

 protuberance in front of their body; and all have powerful jaws, com- 

 posed of many sharp and notched pieces. 



These rascals, fully armed and almost invulnerable, do not do as much 

 harm as might be expected, for they prefer to feed on dead bodies, even 

 such as have already begun to decompose. Do not let us criticise this 

 morbid taste too harshly. The crustaceans and some other animals have 

 the duty to keep the shores of the sea clean, and for this very reason 

 they are possessed of this desire for decaying flesh. Everything which 

 the waves of the sea cast on the shore, and which the action of the at- 

 mosphere decomposes, falls a prey to the swarms of crustaceans, which 

 can live out of the water for a considerable length of time. 



It sometimes happens that the waves cast the dead body of a whale 

 ashore. What great injury might be caused thereby? The air, for a 

 great distance, becomes impregnated with the mephitic exhalations aris- 

 ing from this enormous mass of decaying flesh. There is danger that 

 the entire region may become uninhabitable, for contagious diseases may 

 be bred by the foul miasma. 



Hut all such fears are ungrounded. The crustaceans are on hand; 

 and on these very occasions it will best be seen in what enormous num- 

 bers they are found in the sea, especially near some of the northern 

 coasts. From all directions they come marching in dense columns, and 

 so great is the number of these gluttons, and so eager are they to get 

 their fill, that all danger of the air becoming foul is speedily averted, 

 and soon nothing is left of the enormous bulk but the skeleton. All this 



