The adult organisation of Paragordius varius. 419 
are modified cuticular cells, with deep-staining, rather elongate nuclei. 
They appear to be sensory, to show nervous connections only in the 
anterior region of the trunk, while the slightly heightened ventral 
hypodermis of the posterior trunk does not appear to be sensory; 
and in the anterior region the cells with nervous connections do not 
follow upon each other in an unbroken row, but are more or less 
separated into groups. On good iron-haematoxylin preparations of 
cross sections (Figs. 22, 25, Pl. 38; Figs. 27, 28, Pl. 39), chromophilic 
nerve fibres enter the hypodermis (Hyp) from the neural lamella and 
break into (apparently intracellular) plexuses in these sensory cuticular 
cells; such plexuses extend as far as the cuticle, and are apparently 
wholly the endings of chromophilic nerve fibres and not derivations 
of the sensory cells themselves. On account of this nervous con- 
nection they may well be considered sensory cells. 
Cells of doubtful function. Small cells with very small, 
circular, rather faint-staining nuclei, found most abundantly in the 
hypodermis dorso-laterally (x Fig. 42, Pl. 39). The form and structure 
of the cell body could not be well determined. These are probably 
a modification of the chromophobic nerve cells. 
Chromophobic nerve cells of the hypodermis. These 
(Chb. C Fig. 42, Pl. 39) are cells essentially similar in structure to 
the small chromophobic nerve cells of the central nervous system: 
there is a faint-staining rounded or oval nucleus, and a pale-staining, 
almost homogeneous cytoplasm. It is difficult to be sure of the form 
of these cells: sometimes they appear unipolar, sometimes bipolar 
(Fig. 39), and in some instances one or two long processes could be 
seen extending out from each of them. Each lies in a clear vacuole, 
close to the inner surface of the hypodermis, and their long axes are 
parallel to this surface. 
The position of these and their number was plotted carefully on 
series of cross sections through various regions of an adult female. 
They are most numerous in the dorsally thickened region of the 
hypodermis, next numerous dorso-laterally, least numerous laterally 
and especially sparse in number ventrally. In the dorsal thickening 
of the hypodermis in 379 sections examined, each section being 62/4 u 
thick, from 420 to 440 such cells were found; the greatest number 
found upon a given cross section was 4 or 5; the greatest number 
found in any 20 consecutive sections was 46, the smallest number, 
8—10. They are scattered more or less evenly but with not noti- 
ceable regularity along the length of the dorsally thickened hypo- 
