THE SEA ANEMONE. 87 



a simple membranous sac, seems to be a continu- 

 ation of the external tissue. 



The arms, of the same structure as the body, are 

 tubular, having a minute orifice at their extremity ; 

 and their interior communicates with a compart- 

 ment between the stomach and the external tissue, 

 or wall of the body. This compartment is divided by 

 longitudinal membranous partitions into numerous 

 chambers, between which there is a free communi- 



SECTION OF ACTINIA. 



Showing the chambered cavity with the eggs on the left. 



cation. This chambered or divided cavity is the 

 respiratory or aerating receptacle, and is filled with 

 the sea water taken in through the arms, and 

 expelled by them when the animal contracts ; a fresh 

 supply being absorbed on the dilating of the body. 

 It appears to be thus under the creature's volition ; 



