342 THE DOLABELLINAE. 
midway of the body-length at the posterior end of the anterior division of the 
body-cavity, being placed nearly transversely above the aorta, and immediately 
behind the anterior border of the liver, in front of and above the oblique body- 
septum, or diaphragm. Externally it is located by the anterior ends of the 
parapodia, being situated just below them and slightly to the right of the median 
line. The complex is of an elongated elliptical form, its double nature being 
indicated by the entrance of the connectives from the pleural ganglia, but no 
other external sign of its composition is evident. The left visceral ganglion 
is placed in front of the right parietal one, the larger and more conspicuous 
nerves emerging from the left end and doubling immediately around the aorta 
and to the rear. The two moieties are connected with the corresponding pleural 
ganglia of the central nervous system by long connectives, the right parietal 
ganglion to the right pleural one by the pleuro-visceral connective, Plate 2, 
fig. 1, pl.-par. con, the left visceral division to the left pleural ganglion by the 
pleuro-visceral connective, Plate 2, fig. 1, pl.-v. con. In addition to the figure 
just cited the complex appears in Plate 3, fig. 2, Plate 4, fig. 1, and Plate 5, ‘ 
fig. 4. 
Visceral nerves—From the left visceral ganglion two nerves arise. The 
first of these (Plate 3, fig. 2, v 7) is given off from the inner posterior end of the 
complex. It soon bifurcates into a more slender ramus which passes forward 
to the peritoneum of the dorsal body-wall, and a stronger one which is dis- 
tributed to the vesicle of Swammerdam or spermatotheca, and its duct. The 
second visceral nerve arises as a very strong trunk from the posterior end of the 
ganglion (Plate 3, fig. 2, v2, Plate 5, fig. 4). It at once divides into two equal 
rami, doubling around below the aorta and to the right, and diverging as they 
pass obliquely backward. The right one of these (Plate 5, fig. 4, v. 2a) crosses 
obliquely backward below the loops of the large hermaphroditie duct. Its 
distribution is best shown on Plate 3, fig. 2. It divides into two nearly equal 
trunks, one of which, 2b, at once bifurcates into nearly equal branches, which 
pass backward and are distributed, the one to the rectum and the adjacent 
peritoneum, the other to the siphon and the peritoneum immediately surround- 
ing it. The second trunk, 2c, sends a branch, 2d, to the peritoneum, and several 
minor ones to ramify among the tubules of the organ of Bohadsch, the extent 
of which is indicated by the dotted line, 0. B. The remainder of the nerve 
curves forward and anastomoses with a branch of the seventh pedal nerve 7b. 
The left one of the two rami (Plate 3, fig. 2, v 2b, Plate 5, fig. 4, »2b) of — 
the second visceral nerve diverges backward from its fellow and sends off a 
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