Chap. II. HABITS OF AURELIA. 77 



the water hy the pressure of those below. Two such shoals, in close proximity, 

 stretched over an extent of about fifty feet. That they were actually spawning 

 was ascertained by raising specimens out of water, when sperm was seen streaming 

 freely from the appendages of their lower surface, and eggs flowing along the channel 

 of their arms. It was about sunset, and the closing night prevented me from ascer- 

 taining how long they i-emained together. The next day they were scattered by 

 the wind, and a few days afterwards immense numbers were found stranded upon 

 the rocks and the long sand-beach at Nahant. 



It might be supposed that the great destruction of these animals by the au- 

 tumnal gales, would put an end to the development of the eggs of the stranded 

 specimens, but this is not necessarily the case. On the contrary, I believe, from 

 the observations I have had the opportunity of making, under such circumstances, 

 that the coincidence of their period of spawning with the stormy season of the 

 year, is a provision to bring them into the proper condition for their future 

 development and growth. Thrown among the rocks, uj)on the sea-weeds, they become 

 entangled and break up ; l)ut, by the time they are torn in pieces, the eggs, which 

 have been accumulating in the little pouches formed by the folds of the margins 

 of the arm, have reached their planula state, and are ready to swim about as inde- 

 pendent animals, as soon as they are cast off. I have frequently raised, in con- 

 finement, eggs and planulte taken from such stranded specimens, found, at low-watei", 

 dry, among the sea-weed. Even from such specimens as had been thrown up on 

 the beach, I have raised young Avhich have gone through the first stages of their 

 scyphostoma state, though the mother animal had been left high and dry for hours. 

 As with the returning tide such specimens are set afloat again, it is evident that 

 their brood may frequently make its escape into the water and undergo their 

 normal development after having been for a time ashore. 



The fate of these 3'oung has already been described in a previous section ; they 

 soon become attached to rocks, dead shells, or sea-weeds, and assume their Polyp-like 

 condition, during which, owing to their strong adherence to their resting surface, 

 they are free from the dangers to which their delicate organization would be 

 exposed during storms. The succession of fine days, along our shores, during the 

 month of October, following the equinoctial gales, is the season during which the 

 planulfe, set free by the decomposition of their parents, float about in search of 

 a resting-place. The winter is the season during which they undergo their trans- 

 formation from the scyphostoma state to that of the strobila, which has completed 

 its growth about the middle or towards the end of the month of February. At 

 this time, the wreath of tentacles which crowns these bodies is cast off, and, during 

 the fair days of that season, in the month of March or early in April, the saucer- 

 like disks of the strobila begin to separate. This takes place earlier or later. 



