Crawford. — Spawning Habits of Spiny Lobster 315 



in three cases at least, the incubation period of the eggs is 

 eighteen days. Probably three weeks is more exact for nat- 

 ural conditions, since the water at this time was very warm. 



It was observed that the remains of the seminal vesicle 

 are picked of¥ a few days after the eggs have hatched. It is 

 thus possible to estimate within close bounds the spawning time 

 of any number of females which may be caught. If conditions 

 are favorable, the females molt ten days or two weeks after 

 the vesicle is picked ofif. Mating takes place, as observed in 

 one instance, shortly after molting, while the shell is still soft. 



The eggs are bright coral red when they are first laid, 

 but they change to brown and finally clear, light gray as the 

 developing embryo absorbs the yolk material. The approxi- 

 mate age of the eggs can be judged by observing their color. 

 The newly laid eggs are slightly oval, measuring about 0.45 

 mm. by 0.5 mm. They increase slightly in size and become 

 spherical as the embryo develops. 



Experiments in artificial hatching of the young were car- 

 ried on at the Biological Station at Key West in 1917 and 

 1918. The first apparatus consisted of boxes made of wooden 

 frames covered with cloth in which a female bearing eggs 

 was placed. The eggs were allowed to hatch and the female 

 was removed when the larvae were observed at the surface. 

 This apparatus proved unsuccessful in rearing the larvae. In 

 1918, more extensive experiments were carried on. A small 

 battery of McDonald hatching jars was set up and supplied 

 with running salt water. A wooden trough was provided to 

 catch the overflow from the jars and a device was developed 

 to keep the water circulating upward from the bottom. 



The eggs were found to be rather difficult to strip since 

 they adhered to the pleopods quite securely. At first, only 

 those eggs which were known to be about to hatch were 

 placed in the jars. It was not difficult to select females bear- 

 ing such eggs, for it was observed that when the eggs are in 

 such an advanced state of development, the females are less 

 active than those bearing newly laid eggs. The females do 



