THE CRAYFISH AND ITS ALLIES 



117 



fifth or sixth moult the little lobsters sink to the bottom, 

 and then begin their journey shoreward. From this time 

 until they are about four inches long, only very few indi- 

 viduals have ever been seen. This is due, it is said, to 

 the fact that they hide deep down among the rocks, where 

 they cannot be dredged. When they are four inches long 

 or so, they become bolder, leave the rocks, and, like the 



FIG. 115. Larval view of lobster, extracted from an 

 egg which was about ready to hatch. The concretions 

 in the intestine are destined to go into the newcuticula 

 after moulting, x 25. From Herrick. 



adults, make burrows for themselves in the sand or under 

 stones. 



Development of Crayfish. The crayfish develops simi- 

 larly to the lobster, from a large egg filled with yolk. 

 The early stages are much like those of the lobster ; but 

 those changes which in the lobster take place during the 

 first three stages of free life are in the crayfish passed in 

 the egg. Consequently at the time the crayfish hatches it 



