544 W. A. HERDMAN AND J. A. OCLUBB. 
nerve from the pedal ganglion on each side, going to the lateral 
integument from which the cerata arise. On the right side 
the latter nerve supplies also the reproductive aperture and 
neighbouring parts. Finally, Pelseneer, in his last note which 
we have just received, states that in all cases the cerata are 
supplied by the pleural ganglia, and he gives as an example 
Janus (Antiope) cristatus.! 
The results of these former investigations, then, depending 
entirely, we believe, upon minute dissection, are puzzling, and 
seem sufficiently contradictory to indicate the need of corrobora- 
tion or correction ; so we have set ourselves to trace all these 
nerves afresh by means of serial sections of such of the types as 
we could obtain, with the results given below. 
The species we have sectionised and examined are Poly- 
cera quadrilineata, Ancula cristata, Dendronotus 
arborescens, Hermea dendritica, Facelina coronata, 
and Tergipes despectus. Most of the specimens were pro- 
cured alive either from the Liverpool Marine Biological Station 
on Puffin Island, or from Hilbre Island near Liverpool. They 
were killed and fixed with Kleinenberg’s picric acid, stained 
with picro-carmine, passed through graduated alcohols, em- 
bedded in paraffin, and cut with the Cambridge rocking micro- 
tome. For the specimens of Hermea dendritica which we 
used we are indebted to the kindness of Mr. W. Garstang, 
M.A., now Berkeley Fellow at the Owens College, Manchester. 
These specimens were collected near Plymouth, were plunged 
for a moment, while alive, into glacial acetic acid, were then 
transferred to a saturated solution of corrosive sublimate for 
half an hour or so, after which they were put through increas- 
ing strengths of alcohol up to 90 per cent. in the usual way. 
They were afterwards stained and sectionised like the other 
forms. 
We shall describe the facts we have been able to make out 
in regard to the origin and distribution of the nerves in each 
form separately under the headings of the genera, beginning ~ 
with those in which the cerata seem to be in their simplest 
1 «Bull. Scientif.,’ t. xxiii, p. 440. 
