Crawford. — Spawning Habits of Spiny Lobster 317 



crowded and that it was impossible to separate the larvae. 

 Consequently, they sank to the bottom in tangled mats and 

 soon died. 



Experiments with newly laid eggs were unsuccessful be- 

 cause they adhered in compact masses which could not be 

 separated. None of them developed to the stage in which the 

 eye of the embryo can be seen. Stripping evidently injured 

 most of them before they were placed in the jars. Under nat- 

 ural conditions, the eggs on the pleopods of the female are 

 manipulated with far greater care. 



Although none of the larvae was reared beyond the first 

 stage, the experiment was important because it showed tfiat 

 fluctuations in the temperature of the water are detrimental to 

 hatching and that the optimum temperature is not far from 75 

 degrees F. This temperature was observed at the hatchery 

 only at night during a rising tide when the water was flowing 

 in from the open sea. This strongly suggested that the tem- 

 perature of the water in which the eggs naturally hatch is 

 about 70 degrees, since the incoming water would rise in tem- 

 perature as it mixed with the much warmer shallow water 

 over the flats, thus accounting for the higher temperature 

 observed at the hatchery. 



This fact is rather important for it tends to disprove the 

 common belief that hatching naturally takes place in shallow 

 water. Extensive observations over a period of two years 

 showed that the fluctuations in temperature of the shallow 

 water are too great and too sudden and that the maximum 

 temperature frequently rises beyond that which was observed to 

 be the thermal death-point of the larvae, viz., 98 degrees F. 

 Although occasional females may stay in shallow water while 

 the eggs hatch, it does not seem likely that any great number 

 of the larvae survive. The fact that large numbers of spawn 

 bearing females are caught in shallow water does not prove 

 that they remain there while the eggs hatch, for it is well 

 known that large numbers of spiny lobsters migrate shore- 



