CCELENTERATA. 



249 



radiating and marginal 



canals. 



fringed with tentacles, furnished with stinging thread- 



cells. The radiating parts are in multiples of four. 



Around the rim are minute colored 



spots, the " eye - specks." In fine 



weather, these " sea - blubbers " are 



seen floating on the sea, mouth down- 



ward, moving about by flapping their 



sides, like the opening and shutting 



of an umbrella, with great regular- 



ity. They are frequently phospho- 



rescent when disturbed. Some are 



quite small, resembling little glass 



bells; the common Aurelia is over a 



foot in diameter when full-grown; Flo . 196 ._ A M edU8a , seeu in 



while the Oyanea, the giant among 



Jelly-fishes, sometimes measures eight 



. , . T 



feet in diameter, with tentacles one 



hundred feet long. When dried, nothing is left but a 



film of membrane weighing only a few grains. 



There are two representative types: the Lucernaria, 



the Umbrella-acaleph, having a short pedicel on the back 



for attachment; tentacles 

 disposed in eight groups 

 around the margin, the 

 eight points alternating 

 with the four partitions 

 of the body -cavity and 



FIG. 197. Lucernaria auricula attached to a the four COl'IierS of the 

 piece of sea-weed; natural size. The one on ,1 , , 



the right is abnormal, having a ninth tuft of HI OH til J HOt ICSS tliail 



eight radiating canals, 



and no membranous veil. The common species on the 

 Atlantic shore, generally found attached to eel-grass, is an 

 inch in diameter, of a green color. Discophora, the ordi- 

 nary Jelly-fish, is free and oceanic. It differs from the 

 Lucernaria in its usually larger size and solid disk, four 



