IG 
THE VOYAGE OF II.M.S. CHALLENGER. 
These arc tlie only connective cords visible externally, the others (cerebro-pedal : 
c/H*. ; cerobro-pleural : edte . ; pleuro-pedal : 2 >dic.) being hidden under the cellular coating 
of tlic centres. It is true, however, that the shrunken part binding together the 
Itmchinl and pedal ganglia, which are far apart from one another, may be called the 
bnichio-pedal connective cord, as in the CEgopsids. But these brachial centres 
(innervating the arms by their anterior part) and pedal centres (innervating the funnel 
bv their postero-ventral part) only constitute a single pair of ganglia as has been already 
proved by the development.' 
In the pleuro-visceral centres should be distinguished : — 
A. The pleural (lateral), from which arise the-pallial nerves (jpl.oi.) and 
B. The true visceral ganglia, from which arise the visceral nerves (PI. III. and 
PI. V., V.U.). 
Flo. M.— Peclo-hrachiftl connective of Ommatotlrephcs ptcropus ; left-hand side view, magnified, i, brachial nerves; ii, 
part of a brachial nen-c coming from the pedal ganglion ; iii, pedal ganglion ; iv, brachial ganglion. 
These latter nerves, which arise separately (PI. V. fig. 2, v.n.), could not be followed in 
Spti'ula peronii. In Spirula retmdata it has been shown that they are closely united 
(Fig. S, xi) to the back of the anus, in the same manner as in the CEgopsids, and not 
by a long “commissure” as in Sepia. They do not, however, at their point of 
junction form a true ganglion, as in the first mentioned. From this junction arise 
• In Ommaltmt replies pterajms ami lUex crAn/lcti, examined for comparison with Spirula, are found, at the 
curface of the {ictlmbmchial connective, ten nervous bundles coming from the pedal centres properly so-called, 
and going each to bo joined to one of the brachial nerves (Fig. M). There is then no need of histological 
roacarche* (like tboiie of Owsjannikow and Kowalevski, Ueher das central nervensystem und das Gehororgan 
dor Opha]o{ioden, Mem. Arwl. d. Sri. St Petersbourg, ser. 7, t. xi., 1867 ; and of Jatta, La innervazione delle 
bracchia dci Ccfiilo|iodi, tioU. Soc. Nniur. Nagioli, anno 3, 1889) to show that the pedal ganglion (or of the 
funnol) contributes to innervate the arms. A similar disposition has already been observed in other CEgopsids 
by Hancock (On the nervous system of Ommastreidies tmlarus, Ann. Mag. Nat. Hist., ser. 2, vol. x., 1852, p. 2), 
iVMMnIt (Todarodca mgittatus [Limk.] Stp., Vulensk. Meddel. naturh. Foren., 1890, p. 238), and Appellof 
(Teatbologischn Ileilr.ige, ii., liergruA Mtiseums Aarsherctning, 1890, p. 8). 
* In the paper; IVIsencer, Sur la valour morphologique des bras et la composition du systemc nerveux 
central dcs CVphaloporlcs {Arrh. de liiol., t viii., 1888), the ganglionic swellings from which arise the pallial 
nctvea have been interi>rete<l os anterior visceral (j). 752), and the value of pleural centres was refused to 
them (p. 749). A re-examination has made evident that all the visceral ganglionic elements form a single 
median maas and that Uio pleural centres are indeed those from which arise the pallial nerves. 
