158 
SYDNEY J. HICKSON AND .1. T. WADSWOETH. 
and text-fig. A, mi.). The arrangement of the niicronuclei in 
the arms and stolon is very irregular. In some specimens they 
are found at fairly regular intervals of 30/t or 40 fi in the arms, 
in others they seem to be in pairs (figs. 9, 10), indicating, 
perhaps, a recent epidemic of division, but in several speci- 
mens we have found clusters of three, four, five, or six micro- 
nuclei irregularly scattered in tlie arms and stolon. In the 
specimens from Birmingham we have noticed that, as a rule, 
more rnici’onuclei are present than in the specimens from the 
Bridgewater canal. In the clusters there are sometimes eight 
or nine micronuclei together, and in one specimen there 
Avere as many as nineteen (fig-. 15). This irregularity in the 
arrangement of the micronuclei has sugg-ested the view that 
they may move about in the living organism. 
In Dendroconietes and in other Acinetaria the micronuclei 
are usually surrounded by a clear area, the “hyaloplasm ” of 
Maupas (fig. 14). Such a clear area is also seen round many 
of the micronuclei of Dendrosoma, but it does not appear 
to be so constant in character as it is in some of the other 
genera. In a former jiaper (16) it Avas suggested that this 
clear area may be due to a shrinkage of the micronucleus in 
preservation, and therefore of the nature of an artefact. 
This vieAv is confirmed by a cai-eful examination Avitli high 
poAvers of the area round the micro.nucleus of Dendrosoma, 
as it shoAvs not the faintest trace of protoplasmic structure 
eA-eu in the most successfully stained preparations. Occa- 
sionally a feAv very delicate strands may be seen stretching 
across the area (fig. 14), indicating, perhaps, a former 
organic connection betAveen the nucleoplasm and the sur- 
rounding cytoplasm. But in addition to the perfectly clear 
and unstainable area Ave can also distinguish a more irregular 
area of cytoplasm around each micronucleus, Avhich is better 
defined in some cases than in others (fig-. 13), that differs from 
the rest of the cytoplasm in being relatiA'ely free from granules 
and stains rather less deeply. It is this outer area Avhich 
serves as a guide to the micronuclei and serA-es to distinguish 
them from other chromatin granules. 
