JELLYFISH.
81
coelenterates in a maelstrom of muddy water, sand, weed and
straw, and the subsequent and frequent rescues of the ephyrae
from the gullets of each other, before one could crawl to bed
at 1 a.m. However, they were ultimately raised up to the
stage of well-developed secondary tentacles and this labour of
Hercules was accomplished.
My note books are not now with me, but the foods accepted
by Cyanea ephyrae, to the best of my recollection, were Rathkea,
Sarsia8 and a minute form of Nereis, besides small Ctenophores,
and each other when I was too late to save them from their
friends. Ephyrae are often found in a very deformed and
defective condition, and such will almost always be Aurelia,
in which the malformations vary very much in number, position
and shape of Rhapolae. The ephyrae are also, sometimes, almost
square. In a large strobila of Aurelia it is possible to see that,
in one or more spots, the ephyrulae there will be defective when
liberated.
Ephyrae, like medusae, are sometimes parasitized by
Amoebae, but I lost very few indeed from disease. They are
also extremely sensitive to sudden changes in salinity or
oxygenation.
As regards the medusae themselves I do not propose to
describe them fully, for reasons of space. Those interested in
this subject will not consider the time lost in reading, in more
important works than mine, fully detailed accounts concerning
them. Briefly then:—
Aurelia (the "moon-jelly" of the U.S.A.) is a transparent
medusa, almost colourless with normally four horse-shoe shaped
markings in the centre, the conceptacles, white, yellow or
purple-brown in colour. Sometimes these are as many as ten
in number. Around the margin of the bell is a great number
of small tentacles, and hanging below the bell are the mouth
parts terminating in three, or four, arms according as to whether
the medusa has developed in the series of 3 or 4. This form is
virtually omnivorous at one time or another in its existence,
and it is parasitized by a crustacean called Hypena. The
marsupia when developed will be found on the manubrial arms.
With this medusa, especially, there is a very persistent and,
8 I. W. Low, B.Sc., deals with the subject in a paper in the Proceedings Roy. Phys. Soc.,
Edinburgh, 1921, p. 226.
B