INNERVATION OF CERATA OF SOME NUDIBRANCHIATA. 549 
origin of the primary pleural and pedal nerves from the ganglia, 
and is immediately below the most anterior pair of cerata. 
The dorsal epipodial nerves also give off small branches to 
the cerata and to the neighbouring integument, and then the 
four nerves continue their course backwards to supply the more 
posterior cerata (see Pl. XXXIV, fig. 26). 
In regard to the pleuro-pedal anastomosis described above, 
it is interesting to note that Pelseneer has found that a junc- 
tion (the cervical plexus) between nerves having distinct 
origins from the pleural and the pedal ganglia is effected in 
Pneumonoderma, and other gymnosomatous Pteropods,! 
and also in Aplysia.’ 
HERM@A. 
In Hermeza dendritica (the opportunity of examining 
which we owe to the kindness of our friend Mr. Garstang) we 
find the epipodial nerve arising from the ventral external edge 
of the pleural ganglion. The anterior part of this nervous 
system is bilaterally symmetrical (see Pl. XX XIII, fig. 20, 
which shows the cerebral, the buccal, and the anterior ends 
of the pedal ganglia surrounding the cesophagus), but poste- 
riorly it becomes very unsymmetrical, as was noticed by Bergh,® 
and as figs. 21 to 25 show. 
The flattened expansion of the lateral edge of the body at 
the base of the cerata in this form is largely occupied by the 
lobes of the ovo-testis, their ducts, and the ducts of the hepatic 
ceca (Pl. XXXIII, figs. 20 and 25). 
The origin of the epipodial nerve is shown in fig. 21, which 
is two sections posterior to fig. 20. The nerve turns upwards 
dorsally at once (fig. 22, ep. n.). It is surrounded by a very 
distinct connective-tissue sheath, which is seen connecting the 
pieces of the nerve in fig. 23. When it reaches the level of the 
1 «Arch de Biologie,’ t. vii. 
7 “Report on the ‘Challenger’ Pteropods,” part 3, ‘Zool. Chall. Exp.,’ 
part lxvi, pp. 43 and 88; also ‘ Bulletin Scientif.,’ 1888, p. 195. 
3 “Beit. z. Kennt. d. Molid.,” viii, ‘ Verhdl. Zool. Bot. Gesell. Wien,’ 
1885, p. 5. 
