248 'ALTERNATE GENERATIONS. 



into the digestive cavity ; and the upper margin 

 spreads out to form a number of tentacles, few at 

 first, but growing more and more numerous, till 

 a wreath is completed all around it. In this con- 

 dition the young Jelly-Fish has been described 

 under the name of Scyphostbma. As soon as the 



Scyphostoma of Aurelia flavidula, the white Jelly-Fish with a rosy cross, com- 

 mon along the coasts of New England. 



wreath of tentacles is complete, a constriction 

 takes place below it, thus separating the upper 

 portion of the animal from the lower by a marked 

 dividing-line. Presently a second constriction 

 takes place below the first, then a third, till the 

 entire length of the animal is divided across by a 

 number of such transverse constrictions, the whole 

 body growing, meanwhile, in height. But now an 

 extraordinary change takes place in the portions 

 thus divided off. Each one assumes a distinct 

 organic structure, as if it had an individual life 

 of its own. The margin becomes lobed in eight 

 deep scallops, and a tube or canal runs through 

 the centre of each such lobe to the centre of the 



