PLATE V. 
Spirula peronii. 
Nervous system ; 
size. 
all the figures are drawn to the scale of four times the natural 
Fig. 1.—Dissection from the dorsal side. 
a.d. White body. 
B.m. Buccal mass. 
bm.r. Retractor muscles of B.m. 
br.r. Retractor muscles of arms. 
E. Orbit. 
f. n. Nerve to the fin. 
g. c. Cerebral ganglia. 
g. s. Ganglion stellatum. 
h. p. Anterior part of the liver. 
h.p. Posterior moieties of the hepatic lobes. 
I. Infundibular collar. 
Int. Integument. 
M. Mouth. 
M.S.m. 
Mesosomatic muscular substance. 
OR. 
(Esophagus. 
o.g. 
Optic ganglion. 
P. 
Wall of the “ episoma.” 
pl.n. 
Pallial nerve. 
p.n.c. 
Perineural cartilage. 
s.b.g. 
Superior buccal ganglion. 
sh.s 1 . sh.s 2 . 
Anterior and posterior parts of the shell sac. 
sh.iv. 
Shell wall. 
spli. 
Siphuncular tubes of the shell. 
sph.m. 
Membranous siphuncle. 
apt 1 , spt 2 . 
The two last septa of the shell. 
s.w. 
Shell wall. 
Fig. 2.—General view of the nervous system, from the dorsal side. 
g.ch.s. Chlamydo-splanchnic (pleuro-visceral) ganglia. 
g.p. Brachial ganglion. 
v.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. Pedal 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. 
^rc.chpra.c^Perineural cartilage cut through, where it roofs respectively over the cerebral and 
chlamydo-splanchnic ganglia. 
pn.c 4 . Lateral broad also of the perineural cartilage. 
pn.c 5 . Median lower process of the perineural cartilage.—Other letters as before. 
Fig. 4.—Side (left) view of the central nervous system, the left half of the perineural cartilage removed. 
ar. Passage for artery. 
c.ch.c. Cerebro-“ chlamydo-splanchnic ” connective. 
cp.c. Cerebro-pedal connective. 
g.p.c. Brachio-pedal connective. 
p.ch.c. Short pedo-chlamydo-splanchnic connective. 
pn.c 3 . Perineural cartilage investing the pedal ganglia. 
x. Cerebro-brachial connective. 
1, 2, 3, 4, 5, Brachial and tentacular nerves.—Other letters as before. 
Fig. 5.—The “ pes anserinus ” and its connectives with the pedal ganglia, the right and left lobes separated 
and spread out.—Letters as before. 
Fig. 6.—The right “ stellate ” ganglion and nerve to the fin. 
ar. Artery to the mantle. F. Fin. 
(3. Inner wall of pallial cavity. v.n.s. Venous sinus. 
