204 BUI^IvETIN OF THE BUREAU OF FISHERIES. 



at low tide have been taken out of bunches of eelgrass at a depth of a few inches only. 

 They frequently dig a shallow hole in the mud under stones, where they can await the 

 coming change with greater security from enemies. Fishermen have frequently seen 

 a cast shell lying on the bottom and have found a soft lobster near by, protected by a 

 rock or bunch of kelp. 



Many of the prawns habitually molt in the early morning while it is yet dark, but 

 lobsters which we have kept in aquaria have cast both by day and at night. Consid- 

 ering the nocturnal habits of the lobsters, we should expect to find the latter practice 

 the commoner in a state of nature. In those captives which Brook (57) observed with 

 great care, the shells were cast off in the night time and partially buried. 



Anderton (5) found that the lobsters transported from England to New Zealand 

 molted mostly at night, their cast shells being usually seen lying upside down on the 

 bottom. The shedders retired to some secluded spot where the water was shallow, and 

 appeared vicious upon the approach of intruders. On the 3d of September, says 

 Anderton, "a male lobster was seen to be behaving in a very pecuhar manner in the 

 shallow end of the pond. It would walk alongside the concrete dividing wall for a distance 

 of about 5 feet, halt, and then turning round would retrace its steps the same distance 

 in the opposite direction. In this manner a rut several inches deep was formed in the 

 gravel and at one end of this the lobster scooped out a hole about 4 inches deep and 

 12 inches in diameter." The water had to be temporarily withdrawn from the pond, 

 but as soon as permitted to do so this lobster resumed its peculiar walk, and continued 

 it through the night and the following day. Molting began at 4.30 p. m. of that day 

 and lasted 35 minutes. The lobster at first lay on its side, with its large claws extended 

 in a direct line with its body, and later turned on its back when the tail, the last part 

 to be withdrawn, was released. The habit of scooping a hole in the gravel was noted 

 on several occasions, when the soft lobster was found lying beside its "shadow." As 

 noted in chapter ix, molting in the females was almost immediately followed by copula- 

 tion, whenever a male was available, and the interval between this act and the laying 

 of the eggs was in two cases observed — 65 days. Molts in both sexes were recorded 

 from November 1 8 to March 3 , but rather more frequently in the warm months of Novem- 

 ber and December. 



THE MOLTING ACT. 



A male "shedder" was caught in the harbor of Woods Hole July 13 and placed 

 in an aquarium. At exactly 2.48 p. m. this lobster began to molt and in 6 minutes 

 was out of its shell. 



When the lobster is approaching the critical point the carapace or shell of the back 

 gapes away a quarter of an inch or more from the tail. Through the wide chink thus 

 formed the flesh can be seen glistening through the old and new cuticle, giving it a 

 decidedly pinkish tinge. Take the lobster up in the hand now and the tail drops down 

 as in death, the strong muscles which bind the pleon to the carapace being completely 

 relaxed. When this stage is reached the time of exuviation is at hand and the process 

 becomes purely automatic, the animal having no control over its own movements. 



