Tanks No. 8, 9, 21, 22 and 23. 
15 
POLYPES {ANTHOZOA). 
If it be difficult to the lay mind to apply the term Sponge to orga¬ 
nisms, which in a living condition are not at all of a spongy nature; it 
will be found equally difficult to picture as Corals anything else than 
the beautiful red and white branches which are displayed as ornaments 
on writing-desks and chimney-pieces. And yet these branches are not 
really the animals themselves; but only the framework which they have 
built themselves, and in which they live imbedded in hundreds or thous¬ 
ands, side by side or one above the other. 
Of the polypes, the animals which build up the corals, the best con¬ 
ception may be gained by examining those forms which are considered 
the chief attractions of the northern Aquaria, namely the 
SEA-ANEMONES (ACTINIAE). 
(Tanks No. 8, 9, 21, 22 and 23.) 
These animals exhibit a cylindrical body, attached by an adhesive 
disk to some fixed object and bearing at its free end numerous very 
mobile tentacles. These encircle an aperture, which serves both as mouth 
and as anus (Fig. 5); it leads into a capacious stomach in which the 
Fig. 5. Anemonia sulcata, ^2 nat. size. Fig. 6. Cladactis Costae, attached to a 
On the right the rock to which it is stone. nat. size. Tank 21. 
attached. Tank 8. 
food is digested. The soft and apparently unprotected polype is really 
very well armed. Many parts of the body, but especially the tentacles 
which serve to catch its prey, are provided with numerous microscopic 
vesicles, the so called stinging-cells, which each contain an acid liquid and 
