268 
J. STEPHENSON. 
sectioning, follicles of the “ blood-glands ” are found numer- 
ously within the cellular masses, even deep amongst the 
chromophil cells of the dorsum of the pharynx. 
The Chromophil Cells and their Transformation. 
— The cells which compose the main portion of the white 
masses on and behind the pharynx are polygonal or irregular 
in shape, 20-25 /n in longest measurement, sometimes separated 
from each other by linear spaces ; such have therefore a 
definite outline. The nucleus, up to 6 fx in greatest diameter, 
is conspicuous, vesicular, with large nucleolus and numerous 
granules of chromatin. The cytoplasm as a whole stains 
deeply but not homogeneously, and the lighter staining or 
non-staining portions of the cells appear sometimes as rela- 
tively large areas which may resemble vacuoles. (A similar 
condition is shown in PL 19, fig. 5, which, however, is from 
P. heterochasta.) 
Besides the cells with definite outline, a number are 
also visible in which the central deeply staining cytoplasm 
shades off into a peripheral region, less deeply staining and 
with a fibrillar structure ; this peripheral region again in 
places is indistinguishable from an intercellular substance. 
Passing inwards towards the pharyngeal epithelium the 
continuity of the cells with the connective tissue, now con- 
siderable in amount, is very evident. The connective tissue 
accompanies the muscular fibres in close association, its 
fibrillas often running parallel with the fibres. The cells still 
retain some of the darkly staining substance (PI. 19, fig. 5). 
Still deeper in the pharyngeal mass there may be no 
stainable cytoplasm in association with the nuclei ; these 
then lie in the connective-tissue. Such nuclei are smaller, 
more irregular in shape, sometimes appearing shrivelled ; 
the nucleolus decreases in size, and may become indistinguish- 
able from the chromatin grains. Appearances suggest that 
some at least of these nuclei break up and disintegrate, 
sometimes by dividing into two small vesicles each with a 
staining granule in its interior, sometimes by becoming as a 
whole progressively more indistinct. 
