28 
ZOOLOGY?' 
Actinians and coral polyps having the same general shape 
and structure. 
The common Actinia of our coast {Metridium margina- 
tu7iiy 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 be 
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are thrust out or withdrawn, and the eye-spots at the base of some of 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 
