120 THE OCEAN WORLD. 
anterior extremity of the young animal; the posterior extremity by 
which it is attached to the mother contracting by degrees, until it 
appears only to touch her at one point. Finally, the separation is 
effected, the parent and the young acting in concert to produce the 
entrance of this interesting young polyp into the world. Each of 
them take with their head and arms a strong point of support upon 
some neighbouring body; and a small effort suffices to procure the 
separation; sometimes the parent charges herself with the effort, 
sometimes the young, and often both. 
When the young polyp is separated from the parent, it swims 
about, and executes all the movements peculiar to adult animals. 
‘The entrance into life and maturity takes place with these beings at 
one and the same moment. Infancy and youth are suppressed in 
this little world. 
In the course of his experiments Trembley found the following 
remarkable fact. 
Upon a young polyp still attached to its parent he observed 
a new polyp or polypule, and upon this unborn creature was 
another individual. Thus, three generations were appended to the 
parent, who carried at once her child, her grandchild, and great- 
grandchild. ; 
“In observing the young polyps still attached to their parent,” 
says Trembley, “I have seen one which had itself a little one which 
was just issuing from its body; thatis to say, it was a mother while 
yet attached to its own parent. I had in a short time many young 
polyps attached to their parents which had already had three or four 
little ones, of which some were even perfectly formed. They fished 
for woodlice like others, and they ate them. Nor is this all. I have 
seen a mother-polyp which had carried its ‘Aird generation. From 
the little one which he had produced issued another little one, and 
from this a third.” 
Charles Bennet, a naturalist of Geneva, says, wittily, that a polyp 
thus charged with all its descendants constitutes a living genealogical 
tree. 
We have just spoken of turning polyps inside out! If one of 
these creatures is thus operated upon while it bears its young on the 
surface of its body, such of them as are sufficiently advanced continue 
to increase; although they find themselves in this sudden manner 
imprisoned in an internal cavity, and they re-issue subsequently by 
the mouth, Those less advanced at the moment of reversal issue 
by little and little from the maternal sac, and complete their career 
of development on the newly-made exterior. 
