HYDRA: ITS ANATOMY AND DEVELOPMENT. 329 
had produced a body of about one-twentieth of an inch in length, 
and appeared like a minute Hydra with arms too big for its small 
body. In fifty-two hours it had secured a firm hold upon the glass, 
and stood perfectly upright, the body growing longer; so that in 
seventy-two hours the head portion appeared but little different from 
what it was before severance, except in size. In ninety-six hours 
after division, the new body produced by the head part constantly 
expanded and contracted, and was then complete. No food was 
partaken of until the ninth day, and at that time several buds 
made their appearance. 
The body (Fig. 89) which had been separated from the head lay 
extended for one hour. At the severed end it remained swollen, 
the lower part gradually became thinner, and in this state it re- 
mained for twenty-four hours. After this time, the upper portion 
assumed the shape of a perfectly round ball, w ith a long and thin 
foot-stalk, as represented in Fig. go. The foot was firmly 
attached to the glass, and it remained in this state for the next 
forty-eight hours, waving to and fro its club-like head. 
The first perceptible change was a small protuberance about the 
centre of the foot-stalk ; and during the fourth day, this enlarged 
to such an extent that it was apparent that a young polype would 
form before the upper portion produced a new head, and this turned 
out to be the fact. 
On the fifth day it lay on the bottom of the tank, fully extended. 
The young bud had grown considerably, and four minute arms 
were perceptible. The upper portion of what I now call the 
parent without the head, had still a rounded or ball-like 
appearance. 
On the seventh day, the young polype had so much grown, that 
it was able to catch its prey, and so helped to feed not only itself, 
but also its parent ; on the following day, the whole body was much 
larger, and at the anterior end, upon the ball-shaped mass, 
three minute arms were discernible, so that it had acquired a head. 
The body also began to swell out, and increased in size very 
much during the next twenty-four hours ; and another bud began 
to make its appearance. On the tenth day, the new head had six 
short arms. 
The bud No. 1 caught food freely, and bud No. 2 grew very 
quickly,—the whole organism becoming very strong and healthy. 
In two more days bud “No. 1 commenced life on its own account, 
and the remaining bud had at this time five arms. The arms, also, 
around the new head were fully grown, and played freely in the 
water, but I did not observe them catch any food. The Hydra 
now was exactly like any other; so much so, that no person 
would imagine it had once formed only a part of one. 
One thing noticed on several occasions was, that when Hydra 
