100 COHN, ON NASSULA ELEGANS. 
that Stein has also observed the development of endogenous 
embryos in Chilodon cucullulus, a near ally of Nassula; in 
this case, however, the embryos were developed in the 
encysted animals, made their way through the cyst in escap- 
ing, and moved with the aid of long cilia; resembling the 
Cyclidium glaucoma of Ehrenberg. 
At the thirty-second meeting of German naturalists at 
Vienna, Stein presented a series of remarkable observations 
on the Acineta-formation from the swarm-offspring of Lowodes 
bursaria, Stylonychia mytilus, Urostyla grandis, and Bursaria 
truncatella (“Tageblatt de Versamml.’ No.3, p. 53). With- 
out any desire of forestalling Stem’s more exact exposition, 
I cannot avoid remarking that the reproductive spherules of 
Nassula elegans, in their tentacular processes, do, in fact, 
present an Acineta-like character, and the more so that they 
are also deficient in vibratile cilia. 
In his interesting memoir on the process of Encysting in 
the Infusoria, Cienkowsky (S. and K. ‘ Zeitsch.’ Band vi, 
p- 3801) has given us the developmental history of a nearly 
allied species of Nassula, which he had previously termed 
N. viridis, Duj. He and Stem have both observed the 
process of encysting in this species, and Cienkowsky states 
that after some time the body of the encysted Infusorium 
breaks up into numerous sharply defined cells, neck-like pro- 
longations from which perforate the wall of the cyst; the 
contents of each cell then divide into a great number of 
monadiform corpuscles (microgonidia), which escape through 
the neck-like prolongation, and disperse themselves into 
water. Should these observations, which fully correspond 
with those of Stem on Vorticella microstoma, (Stein, 
“ Infusor.” tab. iv, fig. 53—56, p. 194), really indicate a 
mode of reproduction in Nassula, that Infusorium would 
appear, besides transverse scission, to possess two wholly 
different kinds of reproductive bodies, whose further develop- 
ment, however, it must be confessed, is quite unknown. 
It is very remarkable how closely the microgonidia ob- 
served by Cienkowsky and Stein in the cysts of Vorticella 
and Nassula, together with their flask-shaped parent-cells, 
resemble the parasitic Chytridia met with in the interior of 
many plants. ‘These are microscopic, unicellular fungi 
whose ‘‘swarm-spores” penetrate the wall of a Conferva- 
Spirogyra-, or <Achlya-cell or of a Closterium, and after- 
wards expand in the imterior of these plants imto spherical 
vesicles, which subsequently throw out neck-like processes, 
with whose aid they break through the organism in which 
they are nourished, whilst the contents of the fungus are 
