8 Dr. A. Krohn on Eleutheria. 
interradial spaces. When the bud has become free, the number 
of gemme increases with its advance in growth, but so that only 
a single gemma is produced in each of the other five interradial 
spaces. In rare cascs a seventh gemma occurs; this usually 
appears to break forth close beneath one which is already far 
advanced in its development. 
Thus the gemmez, when their number amounts to six—which 
I observed only in asexual individuals, and then but seldom— 
alternate very regularly with the arms, and present very different 
grades of development, according to the time at which they ap- 
peared. 
In concluding the present memoir, I can boldly assert that 
Eleutheria belongs to the Medusze. In support of this opinion, 
which was accepted by many modern naturalists even before 
the discovery of the parent polype, I have brought forward 
further proofs, of which the discovery of the gastro-vascular 
system, the information as to the sexually-produced brood, by 
which a sensible gap in the developmental history of the parent 
polype is filled up, and the evidence of a gemmiparous reproduc- 
tion, issuing originally from the gastro-vascular system, may be 
particularly indicated as important*. 
It is true that Hleutheria differs from the other Meduse, in 
no small degree, by the absence of an organ of propulsion or 
umbrella; but this deficiency stands, as no one will deny, in the 
fullest accordance with its mode of life. 
Nevertheless, by the aid of the imagination, Kleutherta may 
be converted into a convex Medusa. We nced only imagine 
* To my knowledge, only one Medusa is as yet known which, like Elew- 
theria, gives off buds in the mature sexual state. This is Sarsia prolifera, 
Forbes (see Busch, ‘ Beobachtungun iiber Anat. und Entw. einiger nied. 
Seethiere,’ p. 7). As another example of this kind, I believe, I must cite 
Geryonia proboscidalis, in accordance with an observation made many 
years ago. During my sojourn in Messina, in the year 1843, I met with a 
female specimen of this Medusa, in which the ends of the peduncle, reach- 
ing freely down into the stomachal cavity as in Liriope, appeared thickly 
beset with buds in various stages of development. ‘The less developed 
buds occupied the upper, and the more advanced ones the lower part of 
the peduncle. In the former only the umbrella and peduncle could be 
distinguished ; the latter had evolved not only the six tentacles, but also 
the marginal corpuscles. All these buds adhered firmly to the peduncle of 
the parent by the vertical pomt of their umbrella. Surprising as it may be 
to see buds sprout forth in the interior of an organ which is destined at 
the same time for the reception and digestion of nourishment, it must not 
be forgotten that the same phenomenon has already been observed in 
another Medusa. This is Agineta prolifera, Gegenb. (* Verhandl. d. phys.- 
med. Gesellsch. in Wiirzburg,’ Bd. iv. p. 209). On the whole, however, 
reproduction by buds appears to be but little diffused amongst the Medusa, 
and, from what has been said above, to be generally limited to the young 
states. 
