The adult organisation of Paragordius varius. 437 
lobes (Fig. 85), the body is also filled with a large-celled parenchym 
quite similar to the relations in the female. But through the greater 
extent of the region where the testes are placed the parenchym has 
quite a different structure and arrangement from that obtaining in the 
female. In the anterior portion of this testicular region the parenchym 
elements show the following arrangement (Fig. 83): a layer of paren- 
chym cells around each testis (Tes); a continuous layer of still larger 
cells just within the musculature (Musc) which is deflected upwards 
in the medio-ventral line by the nerve cord (N.C), and which cor- 
responds in position to the perienteric membrane of the female; a 
layer bounding the ventro-median body cavity (JZ V. Cav) on its dorsal 
aspect; and on each side of the body a layer concentric with and 
lying between the first two layers named, this layer disappearing in 
the hinder part of the testicular region of the body (Fig. 84). The 
cellular spaces of these parenchym elements are relatively very large, 
the smallest being those lining the dorsal side of the nerve cord (the 
latter similar to the corresponding cells in the female). The nucleus 
is rich in chromatin and proportionate in size to the cell cavity, the 
cytoplasm rather more in amount than in the female and generally 
close to the wall of the cellular space (this position probably an arte- 
fact due to the fixing reagents) but sometimes beautifully alveolar ; 
in the figures such cells as show no nuclei and appear to be densely 
filled with the cytoplasm, are in reality of the same structure as the 
others but have been cut near their surfaces. But what is especially 
characteristic of the parenchym of the male is the comparatively large 
amount of the intercellular substance (compare the Figures of PI. 43). 
This is dense but granular in structure and so not homogeneous as 
in the female; and what is not shown in the figures made from 
better preserved specimens, but which is to be found in more or less 
macerated individuals (such as those fixed in FLEMMING’s fluid), 
bounding lines are seen to separate the concentric layers of the 
parenchym. The parenchym cells do not appear degenerate and filled 
with dark globules such as is frequently the case in Gordius and 
Chordodes. 
The male in regard to its body cavities and parenchym layers is 
thus quite different in appearance from the female, and this difference 
seems to be mainly due to the absence in the adult male of the 
lateral body cavities, which in its turn may be induced by the dif- 
ferent structure of the genital organs. 
Enveloping the vasa deferentia (Vas Fig. 89, Pl. 43) are sheaths 
