Reproduction of Eleutheria, Quatref. 5 
likewise evidently under the influence of the constantly changing 
state of contraction of the arms themselves, and undergo many 
deviations in consequence. In the other sections of the gastro- 
vascular system similar currents are scarcely to be distinguished, 
on account of the far closer approximation of the brown corpus- 
cles already repeatedly mentioned. Still I saw them quite di- 
stinetly in many parts of the annular vessel*. 
Eleutheria propagates partly by eggs, and partly by buds. 
The former of these modes of reproduction was observed by 
ai and recently confirmed by Hincks. I shall notice 
it first. 
The place of formation of the ova is the whole upper wall of 
the body-cavity, or the dorsal surface. Here, between the ecto- 
and endoderm, the ova are produced, and here they pass through 
all the stages of development up to the maturity of the embryos. 
The seat of the production of the ova is therefore at the same 
time the brood-chamber. 
The youngest ova seen by me were met with in a not yet 
fully mature individual, which contained about thirty of them. 
The careful investigation of a few of them gave the following 
results :—Some appeared to be of a rounded, and others of a 
more oval form, but all were of the same size, which might be 
about 7. mill. In the midst of the granular yelk, which ap- 
peared dead white by direct light, an accumulation of rather large, 
apparently solid corpuscles could be distinguished, intermixed 
with rather smaller spherical vesicles, which had the aspect of 
reddish-brown oil-drops. Each egg was surrounded by a delicate 
envelope (chorion), separated from the yelk by a small interval. 
_ Of the segmentation of the yelk I have only scen two of the 
later phases,—namcely, that known under the name of the mul- 
berry-form, and one rather less advanced. In this latter stage 
the yelk was already divided into numerous globules of segmen- 
tation, but these were still comparatively large and marked off 
from each other by sharp and here and there polygonal boundary- 
lines. Each globule also appeared to contain the well-known 
central nucleus. All the eggs engaged in segmentation were 
considerably (almost two-thirds) larger than the egg-germs 
above described. 
The embryos contained in the same parent animal are for 
the most part in dissimilar stages of development, which leads 
to the conclusion that the ova are successively produced. Hence 
as the number of embryos increases, and as the period of their 
* Although I found it impossible to demonstrate the presence of cilia 
in the gastro-vascular system, I recognized them most distinctly on the 
inner wall of the body-cavity. Here they appear as extremely fine and 
comparatively long filaments, which, however, are much scattered. 
