Notes on Meduse of the Western Atlantic. [51 
of the larval forms, their multiplication and metamorphosis, but he lacked 
material for a study of the development of the sexual organs in the adult, 
and the early larval phases. Indeed, strangely enough, there seems to be 
no certainty as to the sexual character of the creatures—whether they are 
hermaphrodite or have separate sexes. The latter condition is assumed to 
obtain by some writers on the genus. 
In the hope of determining some of the main points in the sexual mul- 
tiplication of Cassiopea, large numbers of medusz were taken from the 
moat and transferred to aquaria and live-cars at the Carnegie Institution 
Laboratory on Loggerhead Key. As Dr. Mayer has beautifully demon- 
strated,t no more favorable material can be imagined for all sorts of labo- 
ratory observations and experimentation than this same Cassiopea. It lives 
remarkably well in small aquaria. 
Parasitic(?) larve.—When the medusz are left for only a short time 
in a jar, and then removed, the water is found to contain floating masses 
or clouds of mucus. Microscopic examination of this mucus shows multi- 
tudes of nematocysts, discharged or intact, singly or in small clusters, float- 
ing init. Also included in this substance, or suspended in the water outside 
of it, there appeared great numbers of very small organisms which I, and 
others, took for embryos of the medusa. These small objects appeared in 
several shapes, suggesting successive stages in growth and metamorphosis, 
and it looked as if it should be an easy task to get the full series of phases 
in the development of the Cassiopea egg. After some days of careful watch- 
ing it was necessary to conclude, in disappointment, that these creatures 
were the parasitic young of some other animal; that they were probably not 
even of ccelenterate origin. 
These organisms were bilaterally symmetrical, not radial, having three 
lobes separated by clear-cut incisions at one end, the larger, and two at the 
other. They were clear, almost entirely transparent, and colorless in the 
earliest stages. With increasing size the number of lobes accessory to the 
first set increases, much as in the echinoderm larva, and there appear in 
the interior of the creature unicellular zoanthellze, which give a yellow and 
later a brown cast to the organism. 
The surface was granular in appearance, a condition which was due to 
the presence of innumerable minute spherical bodies, arranged in regular 
pattern, suggesting in a general way the follicle cells of ascidians. Around 
the margins of the rounded lobular projections, cilia in bands served to 
drive the larva through the water in a rotating motion. Comparison of 
these objects with the ovarian eggs of the medusa, together with a consid- 
eration of the surface appearance and the peculiar contour of the body, made 
it impossible to regard this organism as of ccelenterate affinities. Further 
_ * Mayer, A. G. 1906. Carnegie Institution Publication, No. 47, Rhythmical Pulsa- 
tion in Scyphomeduse. 
