The adult organisation of Paragordius varius. All 
Anterior nerves. In one individual the arrangement of these 
was as follows: From the dorsal anterior edge of the ganglion arise 
two pairs of nerves, the more median much the larger and close 
together. As each of these continues cephalad it subdivides into 
smaller nerves, all continuing within the cloacal epithelium close to 
its basement membrane; these become anteriorly more numerous and 
smaller, and, as in the other individuals, cannot be followed as far 
forward as the anterior end of the cloaca. In another individual there 
are two or three pairs of these anterior nerves; in a third, two pairs 
as in the first; in a fourth individual, two pairs, of which the middle 
pair are united together in the middle line for a considerable distance, 
but separate anteriorly. Thus there is some individual variation in 
the exact arrangement of these nerves. 
Posterior nerves. These (P. Cl. N Fig. 36, Pl. 39) arise from 
the dorsal margin, some from the dorso-anterior, others from the dorso- 
posterior margin, and course caudad within the cloacal epithelium of 
the lateral tail lobes; none were seen in the dorsal tail lobe; they 
lie in the cloacal epithelium close to its basement membrane, and 
cause outward projections of the latter. In one individual there were, 
close to the ganglion, 1 to 2 on the left side and 4 on the right; 
further caudad their number increases, apparently by ramification, and 
they become smaller, until from 10—12 in the right and 8—9 in the 
left lobe can be distinguished. Some of these could be followed quite 
to the end of the tail lobes. Their diameters vary on successive 
sections probably owing to unequal pressure on the part of the cloacal 
cells, and they shift their positions, even apparently anastomosing 
posteriorly, and the more lateral of them ascend within the cloacal 
epithelium to about half way between the dorsal and ventral side of : 
the cloaca. In another individual they were less numerous, so that 
they not only vary in different individuals, but also do not show a 
strictly symmetrical grouping in the same one. 
Structure of the ganglion (Fig. 36, Pl. 39). The anterior 
end of the ganglion is structurally similar to the ventral nerve cord, 
of which it is only a specialisation, but more posteriorly the chromo- 
phobic nerve cells (Chb.C) become more numerous and are arranged 
mainly in its dorsal half and along its dorsal margin. These cells are 
like those of the nerve cord, except that no giant cells occur in the 
ganglion. The chromophobic cells (Chl. C) are less numerous than in 
the nerve cord, but have the same relative position as in the latter, 
1. e. near the insertion of the neural lamella. The chromophobic fibres 
