134 



are drawn entirely from the 



of two successive 



canile . are drawn entirety nom me experience 

 Beasons. 



Lobsters spawn at a definite period of the yar. In ISSO eggs were 

 laid from about June 20th to July lath ; in 1890 from July 1st. to 

 about August 20th the greatest number extruding their eggs during 

 the latter part of July (Jl. 21 — Jl. 31.). The eggs are carried by the 

 female throughout the fall, winter, and spring, and are not hatched 

 under natural conditions until the following summer. 



Copulation precedes oviposition by a considerable period, at least 

 eight weeks in the case of a lobster which laid eggs while kept in an 

 aquarium at the Station. These eggs were fertile, but were scratched 

 off in the course of a few days so that their development was not follow- 

 ed. The eggs when laid are free, and enclosed by a single membrane, 

 the chorion. A second membrane, the membrane of attachment, is 

 added to the eggs, as in related forms, outside of the ovary. The num- 

 ber of eggs varies from about 3000 to upwards of 3G000, depending 

 largely upon the size of the lobster. A lobster 10y 2 inches long pro- 

 duces, on the average 12000 eggs. The hatching period extends from 

 6_8 weeks, from about May 15th to July 1 5th. The bulk of the eggs 

 are hatched under natural conditions in June, and probably during the 

 first half of this month. 



The lobster does not breed annually. This is abundantly proved 

 by the slow growth of the ovarian eggs , by the immature condition of 

 the ovaries at the time when the young are hatched . and by the large 

 percentage of non-egg-bearing females taken in winter and spring. 

 In May, ISS'.t 942 lobsters were taken at Woods Holl by Mr. Vinai N. 

 Kd wards. About ten percent of these were females with eggs. In 

 June 21S4 lobsters were caught, only about -04 percent of which were 

 egg-bearing females. This is explained by the fact that the eggs begin 

 to hatch in June. These and other facts such as the excess of females 

 over males is shown by the following table. 



Table I. 



