PLATE V. 
Spirula j^cronii. 
Nervous system ; all the figures are drawn to the scale of four times the natural 
size. 
Fig. 1. — Dissection from the dorsal side. 
a.<l. Wliite body. 
7i.Ni. Buccal mass. 
bm.r. Retractor muscles of B.m. 
br.r. Retractor muscles of arms. 
K. Orbit. 
f.n. Nerve to the fin. 
(j.e. Orebral ganglia. 
;/.<!. (Janglion stellatum. 
h.p. Anterior part of the liver. 
h.p. Posterior moieties of the hepatic lobes. 
/. Infumlibular collar. 
Ini. Integument. 
M. Mouth. 
M.S.7H'. 
Mesosomatic muscular substance. 
OP,. 
CEsophagus. 
o.g. 
Optic ganglion. 
P. 
Wall of the “ episoma.” 
pl.n. 
Pallial nerve. 
p.n.c. 
Perineural cartilage. 
s.h.g. 
Superior buccal ganglion. 
sh.s^. sh.s^. 
, Anterior and posterior parts of the shell sac. 
sh.w. 
Shell wall. 
sph. 
Siphuncular tubes of the shell. 
spjh.vi. 
Membranous siphuncle. 
spf^. sp>fi. 
The two last septa of the shell. 
s.w. 
Shell wall. 
Fig. 2. — General view of the nervous system, from the dorsal side. 
g.eh.s. Chlamydo-splanchnic (pleuro-visceral) ganglia. 
g.p. Brachial ganglion. 
r.n. Visceral nerves. — Other letters as before. 
Fig. 3. — Side (left) view of the central nervous system, with the perineural cartilage cut through. 
a. Anterior salivary gland. 
A.u. Otocyst 
g.p. I’edal ganglia. 
g.p'. “ Pes anserinus ” : brachial ganglia. 
i.n. Infundibular nerve. 
o.g. Right optic ganglion. 
o.g.p. Peduncle of left optic ganglion cut through. 
/Ni.ch^/n.c^.Perineural cartilage cut through, where it roofs respectively over the cerebral and 
chlamydo-splanchnic ganglia. 
pn.r*. Ijiteral broad alae of the perineural cartilage. 
pn.r^. Median lower process of the perineural cartilage. — Other letters as before. 
Fig. 1. — Side (left) view of the central nervous system, the left half of the perineural cartilage removed, 
or. Passage for artery. 
r.ch.r. Ccrebro-“ chlamydo-si)lanchnic ” connective. 
cp.r. Cerebro-|>edal connective. 
g.p.f. Brachio-j)odnl connective. 
p.rh.r. Short podo-chlamydo-splanchnic connective. 
pn.r*. Perineural cartilage investing the pedal ganglia. 
Cercbrf>-hrachiHl connective. 
1, 2, 3, I, 5, Brachial and tentacular nerves. — Other letters as before. 
Fig. 5. — The “ IX* anserinus ” and its connectives with the pedal ganglia, the right and left lobes separated 
and spread out. — Letters as l>efore. 
Fig, 6. — The right “ stellate " ganglion ami nerve to the fin. 
ar. Arteiy to the mantle. F. Fin. 
p. Inner wall of luxllial cavity. v.n.s. Venous sinus. 
