INFANT FORMS. 269 



find numerous colonies of these tiny creatures crowded 

 together. 



At length a change takes place. The body enlarges 

 both in length and thickness, and begins to show traces 

 of rings or segments, as if it had been tied tightly round 

 with threads at regular intervals. In this stage it has 

 been described under the name of Scyphistoma,* These 

 cuts deepen, and the segments thus marked off become 

 hollow ; and so they resemble a pile of tiny saucers set 

 one within another, each of which is now divided at its 

 rim into eight teeth. In this stage it has been once 

 more named, as if an independent animal, Strdbila. 



All this time the tentacles have been set around the 

 terminal margin, but now these are absorbed, and a new 

 set rapidly spring from the basal segment. The saucers 

 become very loosely attached; at length the end one 

 breaks away and swims through the sea, as a true Me- 

 dusa, though no more than a sixth of an inch wide, 

 pumping as it goes in proper parental wise. Others 

 quickly follow, and thus a colony of tiny swimming 

 jelly-fishes are shooting hither and thither in the live- 

 liest manner. Strange to say, these little Medusae, which 

 as to details differ much from their adult form, have 

 been again described, under the name of Ephydra ; all 

 these appellations indicating the assumptions of vari- 

 ous naturalists, who found the little creatures in their 



