25 



and in function. Thej^ still present certain spines, which, like 

 those of the preceding stages, are employed to assist in ecdysis. 



The protozoeae are pelagic, and the megalopa is still to a large 

 extent pelagic, but it is beginning to take an interest in demersal 

 conditions. The protozoea stages may be said to last about a 

 month, and thus for a period of a month or six weeks the shore 

 crab is undergoing a denatant migration along the coast. At 

 the end of this denatation in the megalopa and the first young 

 stages it is showered in immense numbers on the bottom for the 

 most part between and just beyond tide-marks. 



Ecd3^ses succeed one another rapidly during the first year of 

 life, as is apparent from Table I. and fig. 6, but these take place 

 in the sheltered condition afforded at the bottom. During the 

 instars moreover the young crab is advancing into shallow water. 



