548 WwW. A. HERDMAN AND J. A. CLUBB. 
from the pedal with the pleural element of at least a part of 
the epipodial nerve (see Pl. XXXIV, figs. 26 and 27). 
We give on Pl. XXXIV, fig. 27, a diagram constructed 
from a series of twenty consecutive sections (Nos. 277 to 296), 
and some others, so. as to show from the left side the pleuro- 
pedal anastomosis, and the origin of the dorsal and lateral epi- 
podial nerves. It shows the origin of a nerve (a) from the 
pleural ganglion, and one (4) from the pedal; both run back- 
wards for a few sections, and then 0 gives off a branch (ce) 
which gradually works up dorsally (still connected with d by 
its connective-tissue sheath in sections 286—289) until it 
comes in contact with (section 290) and eventually joins (section 
296) a, the nerve from the pleural ganglion. Previous to this 
anastomosis, however, a gives off (section 291) a dorsally 
directed branch (d), which therefore contains no admixture of 
pedal element. In this way three nerves are formed (seen in 
section 296) on each side of the cesophagus :—the dorsal one (d.), 
which is purely pleural in origin ; the ventral one (0.), which is 
purely pedal; and the middle one (a. + c.), which is partly 
pleural and partly pedal. It is with the first and last of these 
that we have to deal; we may call them, from their positions 
further back in the body, the dorsal and the lateral epipodial 
nerves (see Pl. XXXIV, fig. 27). 
Both of these nerves, on each side, go to the cerata. They 
can be traced back for some distance lying freely in the body- 
cavity, at first the dorsal and lateral being close together, and 
then becoming widely separated (seen at a point about fifty 
sections behind where the nerves become distinct). About 
thirty sections further back still (in section 371) the four 
nerves begin to approach, and then to sink into the body-wall, 
where they take up definitely dorsal and lateral positions 
respectively. They run in this condition through a great 
number of sections. In about the 440th section we find a 
branch arising from the lateral epipodial nerve, which passes, 
in the next few sections, upwards dorsally to enter the first 
ceras where it breaks up (see Pl. XXXIV, fig. 26). This is 
now between 160 and 170 sections posterior to the point of 
