292 REPORT OF THE COMMISSIONERS OF 



of the lobster's existence this function is often exercised in a comparatively- 

 short time, while later it occurs only at long intervals. Moulting in the lobster 

 consists in throwing off the entire external skeleton, together with the lining of the 

 digestive tract. 



" The first moult takes place about the time the young emerges from the egg, when 

 it is about a third of an inch long, and many lobsters do not survive this. During this 

 first stage the larval lobster swims at or near the surface. A second moult eusues in 

 from one to five days, and the lobster enters on its second stage, its average length 

 being about two fifths of an inch and its habits similar to the first stage. In two to 

 five days another moult takes place, and the length of the larva increases to about half 

 an inch. This is followed in two to eight days by another moult, and the lobster enters 

 on the fourth stage, when its length becomes slightly greater. From ten to twenty 

 days later the fifth moult ushers in the fifth stage, after which the surface-swimming 

 habit is discarded and the larva goes to the bottom and begins to assume the charac- 

 teristics of the adult. This stage lasts eleven to eighteen days, and in it the young 

 lobster has attained a length of about three fifths of an inch. From this time on the 

 moults are at longer intervals, until the fully mature condition is reached, when shedding 

 takes place only once in one or two years. 



" The food of lobsters during the larval stages consists chiefly of small crustaceans. 

 A very pugnacious instinct then characterizes them, and active cannibalism prevents 

 their artificial rearing for lack of abundant natural food. 



" Larval lobsters are very susceptible to the influence of the sun (heliotropic) while 

 in the first three stages, being attracted by bright rays to the surface of the ocean or 

 to the side of a vessel. This peculiarity is lost during the fourth stage. 



"During the first year the young lobster, which since the fourth stage has become 

 more and more like the adult in form and habits with each moult, attains a length of 

 .about two or three inches. At the end of the second year the length is five to seven 

 inches. By the end of four and a half or five years a length of about ten inches is 

 reached. The rate of growth, however, depends greatly on the environment, the 

 abundance of food being a very important factor. 



"The adult lobster usually moults in summer, and in the case of the female, shortly 

 after the hatching of the eggs. As several months are required for the new shell to 

 acquire the hardness of the old ; as newly laid eggs are rarely found on a soft-shell 

 lobster; as moulting does not ensue while the eggs are on the swimmerets; and, further- 

 more, as dissection has shown that the ovaries of a lobster whose eggs have recently 

 hatched are in an immature condition, and will not yield eggs until the succeeding 

 year, it follows that the mature lobster deposits eggs not oftener than once in two 

 years, with an alternating moult. 



