The Story of Some Strange Animal Colonies 123 
in all respects to that from which they sprang. 
Others, however, never sow them wild oats, but 
always remain restless roving creatures, yet these 
ead-about jellies have no mind to be outdone in 
the colony-forming way by their more peaceful and 
stay-at-home brethren, so they produce eggs, which 
in time tum first to other little jellies called 
Planulas, and then to hydroids, resembling the | 
parents of the jelly-fish. ; 
But these eggs are not the only offspring of 
the gay and restless little medusa, for by a process 
of buds which form around its mouth, underneath 
and around its disc, this remarkable little creature 
produces a series of other little jelly-fish, like unto 
itself in both form and habit. ‘ 
Though with the majority of the hydrozoa A colony of some eighteen thonsand 
2 9 Moss Animals. 
the baby medusze escape and lead for awhile a 
roving life, it is not the case with all; for instead of the little round bodies escaping 
the moment the lid of the cup is opened, they remain and grow at home, looking 
like miniature jelly-fish stuck fast by their backs to the parent stem. 
All through the long summer months the jelly-fish have a real good time, 
swimming lazily about and feasting to their hearts’ content upon the countless swarms 
of animal hfe that dwell in the sea. As the autumn approaches with its tempestuous 
seas, In which the fragile jelly-fish soon perish, tiny hydras begin to appear upon the 
rocks at about low-water mark, and these baby hydras have come from the little oval 
or roundish eggs which the jelly-fish carried in those four white, or ruddy, round spots 
which all jelly-fish have on the top of their bodies. 
Totally unlike them parent in appearance, these little hydras first settled on the 
rocks as tiny, oval or oblong planulas, clothed with long hairs which they had used to 
propel them to their resting-place. Once comfortably settled, the little creatures 
underwent considerable changes in shape; their outer skin formed into a kind of basin- 
shaped cavity on the top of the body and by-and-bye became the stomach of the animal. 
Then around the edge of this hollow cavity little slender arms or tentacles grew 
out like so many rays, making the creatures look like tiny sea anemones in outward 
appearance, though there the resemblance ended, for these little creatures are all mouth 
and stomach. Throughout the winter these tiny Wx 
hydras live secure from the violence of the heavy - S 
seas which so quickly batter their parent jelly-fish 
to pieces. As the spring approaches the hydras 
are seen to have grown in length and to have 
developed many waist-like constrictions in their 
tube-shaped bodies. In a little while the portions 
between the constrictions become marked with 
eight lobes, making the creature’s body look like 
a pile of saucers placed one over the other. At 
last, round the lowest saucer-like piece which 
attaches the hydra to the rock, some tentacles 
appear, and then all the saucers above break off, 
separate, and turning upside down, are seen- to 2 
have become tiny jelly-fish, and these minute is 
jelies in the course of time grow into the large A portion of a living colony of Hydrozoa, 
