176 Dr. C. Claus on the Ephyre of 
strated that Strobile differently constructed from them do not 
exist, especially as, in the remarkable Stephanoscyphus mira- 
bilis, we know of a polyp which is comparable with the Scy- 
phostoma, and which, in consideration of the four gastral 
pads, might actually be judged to be an Acalephan nurse. 
It is no better with our knowledge of the development of 
Rhizostoma, with regard to which the statements given by 
Noshin * and A. Kowalevsky t have not even settled the 
question whether or not a process of strobilation occurs. 
Under these circumstances I was much interested in a 
statement in the zoological ‘ Jahresberichte,’ according to 
which G. Du Plessis} had recently succeeded in demon- 
strating in Cotylorhiza the occurrence of the alternation of 
generations characteristic of most Acalephs. However, IL 
learned from the statement of Du Plessis just referred to, that 
this observer also had really not got beyond the rearing of the 
Scyphostomes, and that the supposed proof rests only upon 
very doubtful considerations. In point of fact, Du Plessis has 
not traced the process of strobilation, but has rather referred 
to Cotylorhiza, without satisfactory reasons, Strobile met with 
in the aquaria of the zoological station (at Naples). Moreover, 
they were neither fully described nor figured ; and the Kphyree 
thrown off by them were so insufficiently described that the 
existing gap is to be regarded as still unfilled. From the 
agreement which the Ephyra shows in coloration with the 
adult Cotylorhiza (Cassiopea) we can evidently not derive any 
data for the determination of their mutual relation any more 
than a general resemblance of the Ephyra to the adult Cassio- 
pea can be made available for the same purpose. Such a 
resemblance moreover does not exist, or it is so distant that 
the same must apply to any other Ephyra. Should the Ephyra 
described by Du Plessis § really belong to Cotylorhiza, the 
description given by that author is, as we shall see, a very 
superticial one, for no intermediate vessels are spoken of, nor 
is there any mention at all of the charging of the entoderm 
* N. Noshin, Bull. Acad. Imp. St. Pétersb. tome viii. (1866). 
+ A. Kowalevsky, “ Untersuchungen iiber die Entwicklung der Ceelen- 
teraten” (with eight plates), in Nachr, der Gesellsch. der Freunde der 
Naturerkenntniss, &c., Moscow, 1875 (in Russian). 
t G. Du Plessis, “ Remarques sur les métamorphoses de la Cassiopée 
borbonniére (Cassiopea borbonica, Dell. Ch.) faites a la Station Zoologique 
de Naples,” Bull. Soc. Vaud. Sci. Nat. tome xvii. no. 86, 
§ Du Plessis, dc. p. 638 :—“ Du reste, ces jeunes Méduses ressemblent 
déja beaucoup a la Cassiopée adulte. Elles en diflérent seulement par 
une bouche quadrangulée, quatre bras simples (au lieu de huit trés rami- 
fiés) et sans sugoirs, et les bords de l’ombrelle beaucoup plus échanerés 
par des profondes découpures,’ 
