182 On the Ephyre of Cotylorhiza and Rhizostoma. 
wandered into the latter. Perhaps also by means of this sup- 
position we may explain the free occurrence of the globular 
ageregations of yellowish-brown cells which C. Keller* has 
recently described in the jelly of his Casstopea polypoides, and 
has interpreted, certainly erroneously, as a peculiar cell-form 
of the mesoderm. 
The mode in which the chlorophyll-bearing algal cells, 
which also float very numerously free in the gastrovascular 
space, get into the entoderm, may be explained withont diffi- 
culty by means of the faculty of amceboid movement now 
demonstrated in the case of the entodermal cells of the Meduse. 
One might indeed imagine an active immigration on the part 
of the algal cells, which also have been known in the state of 
swarming; but the well-marked amceboid movements of the 
entoderm, which are so important for the inception of corpus- 
cular elements, fully suffice to explain their introduction. 
Perhaps we may even succeed in obtaining this demonstration 
by direct observation ; and for this purpose the Hphyra-stages 
may be particularly well fitted, as their gastral lining is not 
yet overcharged with zooxanthelle., At a later age the filling 
up of the epithelium, especially in the close vascular ramifi- 
cations, is so complete that one must take a good deal of 
trouble to find a free entodermal cell, at least in this section 
of the gastrovascular apparatus. ‘The arms and funnel-frills 
also, as well as the central stomach and the filaments, contain 
the foreign guests so densely packed, that one is led to ask 
the question, whether there is any independent animal nourish- 
ment, and whether the superfluous assimilation-products of 
the zooxanthelle, brought to the entoderm, do not suffice for the 
support of the Medusee. With regard to this question, young 
Cotylorhize, which may be very well kept for months in the 
aquarium, would certainly be favourable objects of experi- 
ment, and would probably in essential .points confirm the 
results obtained by K. Brandt} by experiments with Anthea 
cereus. 
Hitherto I have not been so fortunate as to find the youngest 
Ephyre of Rhizostoma, which have been sought after for years. 
However, I succeeded in obtaining a young form, 34 millim. 
in diameter, which is notably inferior to the known and de- 
scribed stage, and by the small development of the velar lobes, 
which are already cleft, shows that the latter do not grow 
* ©. Keller, “ Untersuchungen tiber neue Medusen aus dem rothen 
Meere,”’ in Zeitschr, fiir wiss. Zool. Bd. xxxviii. 1883. 
+ K. Brandt, “Ueber die morphologische und physiologische Bedeu- 
tung des Chlorophylls bei Thieren,” in Mittheil. aus der zool. Station zu 
Neapel, Bd. iv. Heft 2 (1883). 
