28 



ZOOLOGY. 



Actinians and coral j.)olyps having the same general shape 

 and structure. 



The common Actinia of our coast (Metridium margina- 

 tum, Fig. 29) is to be found between tide-marks on rocks 

 under sea-weeds, or in tidal pools, but grows most luxuri- 

 antly on the piles of bridges. It readily lives in aquaria, 

 where its habits may be studied. An aquarium may b< 

 improvised by using a preserve-jar or glass globe, covering 



Fig. 29. — Common Sea-Anemone. Natural size, with the tentacles expanded. 



After Emerton. 



the bottom with sand, with a large flat stone for the at- 

 tachment of the sea-anemone. By placing a green sea-weed 

 attached to a stone in the jar, and filling it with sea- water, 

 the animal may be kept alive a long time. 



After observing the movements of the crown of tentacles as they 

 are thrust out or withdrawn, and the eye-spots at the base of some of 

 the tentacles, specimens may be killed expanded by the gradual intro- 

 duction of fresh water, or by plunging them into picric acid. They 

 should then be transferred to the strongest alcohol, and allowed to 



