INNERVATION OF CERATA OF SOME NUDIBRANCHIATA. 6543 
b] 
processes, be they ‘‘ epipodia”’ or “ pleuropodia,” are truly 
pedal structures, like the lateral processes in the Rhipido- 
glossa, in the sense of being innervated from the pedal centres. 
The present knowledge of the matter from literature, restrict- 
ing the question now to the cerata of Nudibranchs, is as follows. 
Alder and Hancock,' in their admirable anatomical plates, 
figure, in the case of Tritonia, large nerves to the dorsal 
integument, which are shown arising from the “ branchial” 
[pleural] ganglia, while the pedal ganglia give off only the 
nerves to the foot proper, and two small nerves to the skin of 
the sides of the body. In Goniodoris they show practically 
the same arrangement, and also in the case of Fiona. In 
Eolis, however, large nerves from the pedal ganglia are 
shown supplying the skin of the sides of the back where the 
cerata arise. 
Bergh, in his important series of detailed papers on the 
minute anatomy of these forms, figures what we take to be 
epipodial nerves in various Nudibranchs. In his “ Beitrage 
z. Mon. d. Polyceraden,” No. 1,? he describes in the case of 
Euplocamus croceus the “n. pallialis” arising from the 
visceral part of the cerebro-visceral ganglionic mass, and giving 
off branches to the cerata. Again, in his “ Die Cladohepa- 
tischen Nudibranchien ” he describes* the ‘‘ n. pleuralis” (or 
‘lateralis ”), evidently the same nerve as the “ pallialis” men- 
tioned above, as arising in Holids from the pleural part of the 
cerebro-pleural ganglia. 
Vayssiére figures* in Marionia (a form closely related to 
the common Tritonia) a nerve from the pleural portion of the 
cerebro-pleural mass on each side, and also an accessory smaller 
1 “Monograph of the British Nudibranchiate Mollusca,’ Ray Society, 
1845—1855. 
2 ¢ Verh. d. k. k. Zool. Bot. Ges. Wien,’ Bd. xxix, 1879, p. 599. 
3 « Zoolog. Jahrb.,’ Bd. v, 1890. 
4 © Atlas d’ Anatomie comparée des Invertébrés,’ Paris, 1888, pl. ix, fig. 3. 
Vayssiére has also described (‘ Arch. Mus. Marseilles,’ t. ii, p. 96) the nerves 
supplying the large “ parapodia” in Notarchus and Aplysia as arising 
from the lateral posterior borders of the pedal ganglia, 
