DENDKOSOMA RADIANS, EHRENBERG. 
173 
so healthy as those that are free from them. On the other 
hand, healthy Urnnlas are frequently found on Dendrosoma 
itself in positions that would not permit them to penetrate 
the delicate unpi'otected ectosarc of the head region, and also 
on other bodies, such as weeds, stalks of Epistylis, etc. We 
have, moreover, never observed a stream of food particles 
passing from the Dendrosoma to the Urnula body in the 
tentacle that is apparently attached to the former, as we 
should certainly find if the latter were feeding parasitically 
upon it. We are inclined to the opinion, therefore, that the 
Urnula is epizoic and not strictly pai-asitic. 
The meganucleus is usually spherical in shape and central 
in position. In one specimen (fig. 40) in which the diameter 
of the body as preserved was 19 q, the diameter of the mega- 
nucleus was 8’5 /n. The chromatin of the meganucleus is usually 
in the form of a network. It never shows the granular character 
that is such a marked feature of the meganucleus of Dendi’O- 
sotna. It i.s sometimes difficult to determine whether a micro- 
nucleus is present or not, but a small deeply staining granule 
about T7 /.i in diameter may frequently be observed in sections 
which we believe to be the micronucleus (fig. 40). No stages 
in its enlargement or division have been observed. 
We have observed the same method of reproduction in 
our specimens as that previously described for the species 
by Claparede and Lachmann. The individual divides by 
oblique fission into two parts, one usually larger than the 
other (figs. 41, 43). Of these the smaller becomes holo- 
trichously ciliated and escapes. The larger may remain in 
the undivided lorica and increase in size until it is again full 
grown. Of this, however, we have no positive evidence. It 
is possible, however, that the escape of the smaller product of 
fission entails the death of the larger product, but if this 
were the case we should expect to find attached to the Den- 
drosoma a certain number of empty loricse. We have, how- 
ever, never found an empty lorica attached to the Dendrosoma 
nor any signs of degenerating protoplasm in a lorica. 
The Urnula was found on specimens of Dendrosoma from 
VOL. 54, PART 2. — NEW SERIES. 13 
