MANUAL OF FISH-CULTURE. 231 



have been found in a lobster's stomach, and algtie sometimes serve as 

 food. Fish is the bait most extensively employed in the lobster lishery. 



REPRODUCTION. 



The reproductive function of the lobster is not generally understood, 

 and until a comparatively recent date a number of important questions 

 in relation thereto were undecided. From the standpoints of the com- 

 mercial fishermen, fish-culturist, and legislator, it is necessary that the 

 principal phases of this subject be clearly appreciated, in order that 

 the supply may be maintained. 



The principal spawning- season for lobsters on the United States coast 

 is summer, especially July and August, when probably three-fourths of 

 the h)bsters deposit their eggs. The remaining egg-producing lobsters 

 lay during the fall and winter. A given lobster does not spawn oftener 

 than every second year, as has been shown by recent studies conducted 

 by the Commission. 



The eggs are fertilized outside the body of the female. The sper- 

 matic fluid is deposited in a receptacle at the base of the third pair of 

 walking legs, and retains its vitality for a long time. When the eggs 

 are being extruded, the female lobster lies on her back and folds the 

 tail so as to form a kind of chamber to retain the eggs. After their 

 discharge from the body, the eggs become coated with a cement substance 

 secreted by glands in the swimmerets; this substance hardens after 

 being in contact with the water and firmly unites the eggs to the hair- 

 like filaments on the swimmerets. The exact method by which the 

 fertilizing i^riuciple is conveyed to the eggs from the pouch in which it 

 is contained is not known. 



The incubative period is much prolonged. After the eggs are 

 extruded and become attached externally, they are carried 10 or 11 

 months before hatching ensues; during this time they are carefully 

 protected, and are perfectly aerated by the active motion of the swim- 

 merets. On the United States coast most of the lobsters emerge from 

 the egg in June, although some of the hatching is completed in May 

 and some in July or even later. A few eggs are now known to hatch 

 in winter. All of the embryos do not come from the eggs at the same 

 time, the hatching occupying a week or more. The young receive no 

 attention from the adults, but lead an independent existence immedi- 

 ately after escaping from the egg. 



The lobster egg is about ^^ inch in diameter. When newly laid it is 

 usually of a dark-green color, but is sometimes light-grayish or yellow- 

 ish-green. 



The known maximum number of eggs produced at one time by a 

 lobster is 97,440; the average from lobsters taken for market is 10,000 

 to 12,000. The number depends largely on the size of the lobster, 

 apparently in conformity to the following rule: The numbers of eggs 

 laid by given lobsters vary in a geometric scale, while the lengths of 

 the lobsters vary in an arithmetic scale. 



