ALCYOtflDIUM ELEGAKS. 363 



ration in the interseptal spaces, or even in the stomach, and 

 there hatched, as it were, into their lasting form. On emerging 

 into the open ocean, they already resemble their full-grown 

 relatives, the only difference consisting in a smaller number of 

 tentacles and septa. The sea-anemones were consequently 

 supposed to be viviparous, an error which more accurate obser- 

 vations have fully refuted. 



Both the Ctenophora and the Sea- Anemones are single or 

 solitary, but the vast majority of the Aclinozoa consist of 

 aggregated animals attached to one another by lateral appen- 



Ale-yonidium elegans. 



Branch to which the polypary ts fixed. b. Fonc. c Trunk, d. Polyp-bearing branches. 

 e. Polyps contracted within the foot. 



dages, or by their posterior extremity, and participating in a 

 common life, while at the same time each member of the family 

 enjoys its independent and individual existence. These com- 

 pound polyps are all either Alcyonarians, in which each polyp 

 is furnished with eight pinnately fringed tentacles, or Zoantha- 

 rians, in which the tentacula are simple or variously modified, 

 and generally disposed in multiples of five or six. The Alcyo- 

 narians are again subdivided into the four families of the Alcyo- 

 nidse, the Pennatulidse, the Grorgonidse, and the Tubiporidae. 

 The AJcyonidsR vary much in form, being either lobed, 



