The adult organisation of Paragordius varius. 457 
fragmented into several portions, sometimes no nucleus at all can be 
seen. The chromatin stains deeply with haematoxylin, is mainly 
limited to the periphery, anc often shows a vesicular arrangement. 
The cytoplasm is often finely granular in appearance, sometimes it en- 
closes large, clear vacuoles. There is an evident cell membrane. These 
cells were not found within the lumen of the intestine or. of the genital 
organs, though some were found imbedded into the surface of the 
supra-intestinal organ (Par. N Fig. 21, Pl. 38). Their occurrence in 
only one individual shows them to be parasites and not free blood 
corpuscles; but whether they are particular stages of the parasites 
found within the cloacal wall remains to be determined. Undoubtedly 
these parasites are such as usually occur in the last host of Para- 
gordius, so that a study of the parasites of Acheta would serve to 
explain their nature. 
In one male there was found imbedded in the sheath tissue of 
the eye a small clear body containing a much curled thick thread 
that stained deeply with iron-haematoxylin; its appearance was very 
similar to the fig. 93 given by SCHAUDINN of the spirem stage of the 
oocyst nucleus of Coccidium ?). 
Literature. No author to my knowledge has described para- 
sites in the Gordiacea. 
XIII. On the Relationships of the Gordiacea. 
In the following discussion the Gordiacea will be considered 
from the standpoint of their adult structure alone. While the early 
development is known to some extent, up to the stage of the larva, 
and while the immature stage found in terrestrial insects (the stage 
which immediately precedes that of the mature organisation) has been 
described, especially by VEJDOVSKY, the long series of changes between 
these two conditions are as yet unknown. Thus while the adult 
structure of the genera Gordius and Paragordius are now known suf- 
ficiently well to allow of comparison with other forms, there is a 
great hiatus in our knowledge of the ontogeny. Until this gap in 
our knowledge is cleared away by future observations, the embryo- 
logy can be of but little service in determining the phylogeny. For 
the stages yet undescribed may be the very ones to prove of most 
value for this inquiry. 
1) Scnaupinn, Unters. über den Generationswechsel bei Coccidien, 
in: Zool. Jahrb., V 13, Anat., 1900. 
30* 
