rl34 NEW YORK STATE MUSEUM 



carried for some time before hatching. The time of laying in 

 the north has, however, not been determined. 



In the lobster, according to Herrick, the eggs are laid during 

 the summer, and they are. not hatched till the following summer. 

 It is possible that it may be the same in the crab. 



As mentioned above, the eggs of the crabs are carried by the 

 female on the under side of the abdomen. They are of exceed- 

 ing small size compared with the size of the crab, and number 

 somewhere between 2,000,000 and 3,000,000. 



The size and number of the eggs of animals depend to a con- 

 siderable extent on the stage which the young has attained on 

 hatching. That is, if the young is hatched in an immature stage 

 and therefore has to pass through a long larval life, where the 

 destruction of individuals is very great, the eggs will have to be 

 sufficiently numerous to compensate for this destruction. Thus- 

 in some of the shrimps, where the young hatch in a form very 

 like the adult, the eggs are large and few. In the lobster, the 

 eggs are relatively smaller and more numerous than in the pre- 

 ceding, and the young hatch in what is known as the schizopod 

 stage, which, while resembling the adult in some respects, still 

 has to undergo a metamorphosis. 



The edible crab, on the other hand, hatches at a very early 

 stage and has therefore to undergo a long larval existence 

 before reaching the adult form. During this period the young 

 are perfectly helpless as far as their enemies are concerned and 

 are therefore subject to very great destruction, which, however,, 

 is compensated for by their enormous numbers. 



The crab at hatching is known as a zoea and differs strikingly 

 from the adult in form. Its body is more rounded and has a 

 large, pointed dorsal spine, an anterior spine between the eyes- 

 and two lateral ones. The eyes also are very large. The abdo- 

 men, instead of being small and folded under the body, is long,, 

 has a forked telson and functions as a swimming organ. No 

 traces of walking legs are apparent, the principal organ of loco- 

 motion besides the tail being two pairs of long swimming legs, 

 which are biramous, covered with long hairs, and correspond 



