Jelly Fishes. 609 
to the orifice of the mouth, and swallowed without 
mercy. 
One of the commonest kinds of these Polyps is the 
Mesembryanihemum (Actinia Mesernbryaniliemum), a large, 
usually liver-coloured species, with a row of blue warts 
round the margin just outside the tentacles. It is found 
abundantly on the rocks of our Southern coast especially. 
The Thick-korned Anemone (Actinia or Brusodes crassi- 
cornis) is another large and fine species, usually of a red 
colour, with very thick tentacles, which are generally 
white with pinkish bands. — The Sea Cereus (Anthea 
Cereus) has long slender tentacles, which are not retracted 
in the same way as those of the Sea Anemones generally. 
The tentacles are usually tipped with a pink or purple 
tint ; they are constantly waving about in the water in 
search of prey, and instantly seize upon any creature 
that passes over them. — The Parasitic Anemone (Actinia 
parasitica) and the Cloak Anemone (Adamsia palliata) 
always attach themselves to univalve shells which are 
occupied bv Hermit Crabs. 
JELLY FISHES. 
The animals commonly known as Jelly Fishes are free- 
swimming Eadiata ; they were described by Cuvier and 
most succeeding naturalists under the name of Acalephce, 
from a Greek word signifying " nettles,''' because many of 
them produce a stinging sensation when they come in 
contact with the skin. Their name in several languages 
signifies "Sea Nettles." The Acalephae of Cuvier are 
now regarded as belonging to the same class as the 
Hydroid Polyps. 
The common Medusa (Medusa amitd), which may serve 
as an example of this group, is found in great abundance 
round our coasts ; it is of a circular form, convex above, 
concave beneath, like an umbrella, the stick of which is 
represented by a thick stalk, containing the mouth and 
stomach, and terminated by four long arms for seizing 
the animal's food. The skin of these, and of the body 
and its appendages generally is full of the thread-cells 
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