218 
\V. A. HASWELL. 
with Dinopliilus than with any otlier annulate animal (see- 
Nelson, 7 , pi. 13, fig. 20). 
Opposite the base of each of the tentacles is a group of 
nerve-cells which give off processes outwards into the tentacle 
and inwards into the neuropile. 
There is a distinct rudimentary visceral nervous system 
(fig. 13, V. n.) similar to that described by Foettiuger a& 
occurring in Histriobdella. It consists of a pair of strands 
of nerve-cells given off from the oesophageal connectives close- 
to their origin from the brain and passing back to the jaws 
and their muscles. 
The cesophageal connectives pass downwards and back- 
wards at the sides of the oesophagus and jaws to meet 
towards the ventral side of the neck-segment in the first 
ganglion of the ventral chain. Each gives off', as above 
stated, close to its origin from the brain a visceral nerve,, 
which, accompanied by a number of nerve-cells, runs back- 
wards among the muscles of the jaw's. 
The first ganglion of the ventral chain (figs. 1-6, n. c.)^ 
situated in the neck-segment, is a very small one and is 
scarcely separated from the next. The ganglion of the second 
segment is of large size, and extends throughout the greater 
part of the length of the segment. Throughout the gi eater 
part of the length of the second segment the nerve-cord is- 
double, being divided by a median vertical fissure, which is 
continued into the connective between the second ganglion 
and the third. Laterally the second ganglion gives off a pair 
of nerves, passing to the small ganglia at the bases of the 
cirri of the first pair. The third ganglion is also a large one, 
and is not divided by any median fissure : it gives off the 
nerves to the second cirri. The connectives between the third 
ganglion and the fourth, which are shorter than those in 
front, are separated by a well-marked median fissure. The 
fourth ganglion in the male corresponds to the claspers, to 
which it gives off a large offset. In the female the corre- 
sponding nerves end in a pair of lateral ganglia. The 
succeeding pair of connectives are separated from one another 
