THE LIVING SPECIMENS IN THE AQUARIUM. 
Ill 
Corallines, or Zoophytes, are compound animals that live upon one 
general structure, frequently assuming a plant-like form. Those most 
commonly known are moss corals , so 
CORALLINES, OR ZOOPHYTES. 
called from their moss-like appear¬ 
ance. In some instances they grow 
upon sea-weeds, completely covering 
their surfaces with small cells, resem¬ 
bling honeycomb. These possess a 
higher organization than the simpler 
polyps , many of which so closely re¬ 
semble delicate sea-weeds, that they 
have freequently been mistaken for 
them. Viewed under the microscope 
these are highly interesting objects; 
specimens enclosed in vials with a lit¬ 
tle salt water may be favorably ob¬ 
served, the animals coming forth 
from their concealment and displaying 
their beautiful and delicate forms. 
The tank will sometimes begin to be coated on the inside with green mat¬ 
ter ; this is a sure sign that you want a few sweepers, or scavengers, among 
your colony. Sea-snails, or periwinkles, are very useful in this department; 
they are active devourcrs of decaying vegetable matter, and will often keep 
the aquarium perfectly free from confervoid growth. They are likewise 
very good, quiet, inoffensive citizens, which is more than we can say of all 
the inhabitants usually introduced into aquaria, some of whom require to 
be very carefully watched, on account of their pugnacious and voracious 
habits. 
The Periwinkle is 
one of the gasteropodous 
mollusks, so called be¬ 
cause of their habit of 
creeping, using the belly 
as a foot. It is well 
known to our young 
friends who have visit¬ 
ed the sea-shore, where 
it is found in great 
quantities. Its eyes, 
unlike those of the land- 
snail, are placed at the 
base of the tentacula, 
instead of at their extremities. Their tongues are long, and armed with 
transverse rows of teeth. Members of this group inhabit all regions of 
the sea, but by far the greater number of them live near the shore, and a 
COMMON PERIWINKLE. 
SPIRAL PERIWINKLE. 
