JOURNAL OF ENTOMOLOGY AND ZOOLOGY 143 
number 3 also going to the tentacle and the sub-pallial ridge, 
and 5 and 6 giving branches to a gland in the mouth muscles. 
Number 4 is a very small nerve which runs forward to the 
muscles of the body wall. The nerves of the pleural portion 
are three in number, the first two originating as one nerve 
which soon branches. They may be called the anterior (7), 
median (8), and posterior (9), mantle nerves, as they supply 
the whole length of the mantle. The main trunk of any of these 
mantle nerves lies in the body cavity, close to the body wall 
for most of its length, but finally passes through the body wall 
and lies near the large lateral blood sinus. Branches cross the 
body wall just below the large sinus, usually between it and 
one of its branches, and run along just outside of it, giving 
off branches to the papillae. These branches usually originate 
near the branches of the sinus and the branches of both systems 
in the papilla are closely connected. The nerves that go to the 
papille are large and have some ganglion cells near their 
origin. They give numerous fibres throughout the length of 
the papilla, and finally terminate around the gland at the apex. 
The pedal ganglia are situated below the posterior part of 
the cerebro-pleural and extend slightly beyond the lateral mar- 
gins, so that they are usually visible from above. They are 
nearly spherical and measure about 250 microns in diameter. 
They are joined to the cerebro-pleural ganglia by two con- 
nectives, placed close together, the fibres of one passing to the 
cerebral and of the other to the pleural portion, and to each 
other by commissures which are closely connected with each 
other and with the visceral commissure for the larger part of 
their course, but have separate origins. The pedal ganglia give 
off a pair of very small nerves that run forward to the body 
wall (14), and anterior (15), median (16), and posterior (17) 
pedal nerve. These run along inside the muscles of the body 
wall at the angle of the side and foot, giving off branches with 
ganglionic enlargements, which branch and rebranch, sending 
fibres to the muscles, skin, and glands of the foot. They also 
give small branches to the muscles of the body wall at the 
side and foot. The pedal ganglia also give off another pair of 
