ACALEPHS. 



SO/ 



tral portion and unite with a circular tube which follows 

 the outline of the periphery of the animal. The external 



of 



edges 



opening are 



492. 



the central or oral 

 turned outward, 

 and more or less prolonged in- 

 to fringe-like appendages. Ten- 

 tacular appendages wanting, or 

 present in almost every de- 

 gree of development both as 

 regards number and extent. 

 Jelly-Fishes, in their most com- 

 mon forms, are known as Me- 

 dusae, and have long been ob- 

 jects of great interest to voy- 

 agers and residents by the sea, 

 as well as to the most learned 

 naturalists. Their jelly-like 

 bodies, scarcely denser than 

 the water in which they move ; 

 their curious and beautiful Jeiiy-Fish, />. 

 forms, and often beautiful colors ; their complicated struc- 

 ture, delighting all who study it ; their movements, varied 

 and graceful as those of the butterfly or the bird of the 

 air ; their phosphorescence by night, making the track of 

 the vessel, and the breakers upon the shore, glow with 

 light, and gaining for them the appellation of " Lamps 

 of the Sea" ; and, above all, their wonderful modes of re- 

 production and development, conspire to excite our in- 

 terest, our wonder, and, as we study them carefully, our 

 admiration. 



In treating this group, we follow Agassiz, in his " Con- 

 tributions to the Natural History of the United States." 



Jelly-Fishes embrace three orders, --Ctenophorae.Dis- 

 cophorae, and Hydroids, ranking in the order named, 

 Ctenophorae being highest. 



Per. & Les. 



