No. 2.] COMPARATIVE CYTOLOGICAL STUDIES. 481 
conclude from their structure what their function is; per¬ 
haps they have a function similar to that of lymph glands. 
Such cells are absent in Montagna.) 
The form of these is a more or less polyhedral one, caused 
by the pressure of the surrounding organs (Fig. 339). The 
nucleus is relatively and absolutely very large and is very vari¬ 
able in form, sometimes irregularly oval, sometimes with obtuse 
or pointed processes, or again concavo-convex, that side being 
convex which lies near the nuclear membrane (on a transverse 
section such a nucleus appears sickle shaped). The chromatin 
is arranged in the form of rather coarse granules (Figs. 339 
and 342), which after fixation in Hermann’s fluid (Fig. 340) 
appear to be the nodal points of a reticulum. 
The nuclei (Figs. 338-346) are numerous, vary in number 
from about six to about forty, and are irregular in size. Their 
shape is usually oval, seldom perfectly spherical, though quite 
frequently, as the figures show, they may be more or less 
elongate or even very irregular in form. Vacuoles are fre¬ 
quently present in them. The nucleoli stain as do all true 
nucleoli, but different degrees of staining density may be 
observed in the nucleoli of the same nucleus (Figs. 338, 342, 
346). In two cases, one of which is here figured (Fig. 342), a 
dense ring of chromatin was found around a nucleolus, but such 
cases, judging from their infrequency, must be regarded as very 
abnormal, if not attributable to the action of the fixing fluid. 
Divisions of the more elongate nucleoli certainly take place. 
Thus I have observed dumbbell-shaped nucleoli in three cases 
(Figs. 343, 345, 346), and Fig. 340 probably represents a stage 
just after a division, where two smaller nucleoli have apparently 
been divided off from a larger one, one end of the latter being 
drawn out to a point. Thus it might seem that the large num¬ 
ber of nucleoli are produced by divisions of a smaller number 
of larger nucleoli. The variability in the size, form, and 
number of these nucleoli recalls those of the subcuticular gland 
cells of Piscicola (cf infra) ; but in these cells of Doto I have 
been unable to make out different morphological phases. 
The cytoplasm of these cells is also remarkably differentiated 
(Fig. 339). In a given cell certain portions of the cytoplasm 
