PLATE III. 
Spirula peronii. 
A vertical longitudinal section, supposed to be taken somewhat to the left of the 
middle line. The left lobe of the liver, left posterior salivary gland, left branchia and 
half of the beaks and lips are removed ; and the section passes through the centre of the 
terminal fossa. Drawn to scale of 4 diameters. 
ad. 
an. 
Au. 
C.P. 
d.b. 
d.i. 
Ep.S. 
/*• 
9P- 
hp. 
hpd. 
I. 
La. 
Ik. 
in. 
Is. 
l.e. 
l.i. 
In. 
M.S. 
MS.m. 
oe. 
o. g. 
op. 
pi pi 
pi 
p~. 
White (adenoid?) body. 
Anus. 
Right auditory sac. 
“ Cephalopodium ” ( = head + foot). 
Dorsal beak. 
Median dorsal infundibular apophyse (nuchal cartilage) 
“ Episoma ” (= visceral sac and mantle). 
Terminal fossa. 
Brachial ganglion. 
Right lobe of the liver. 
Duct of the right lobe of the liver. 
Infundibulum. 
Infundibular collar. 
Ink hag. 
Intestine. 
Infundibular attachment. 
External lip. 
Internal lip. 
Lingual portion of the odontophore. 
“ Mesosoma ” (connecting the Cephalopodium with the Episoma). 
Mesosomatic muscular wall. 
(Esophagus. 
Optic ganglion. 
Optic nerve. 
P 5 . Edges of the mantle at the shell openings. 
Mantle aboral disk behind the shell, with the terminal fossa. 
Shell-secreting surface of the mantl'e. 
P s . 
p.c. 
P.d. P.l. 
pn.c. 
p.s. 
p.sl. 
ptn. 
P.v. 
rd. 
sh. 
sph. 
spt 1 . spt 2 . 
st. 
T. T. 
v.b. 
v.n. 
w". 
I, II, III, IV 
IV'. 
Part of the mantle reflected over the ventral wall of the anterior chamber of the shell, 
in the middle line. 
Pyloric caeca (“ pancreatic follicles ”). 
Dorsal and lateral lobes of the free edges of the mantle. 
Perineural cartilaginous capsule, cut away on the left side to show the left optic 
ganglion with the nerves proceeding from it. 
Spiral pyloric appendage or “ pyloric sac.” 
Posterior salivary glands. 
“ Peritoneum.” 
Ventral edge of the mantle. 
Radula. 
Shell. 
Siphuncle of the shell. 
Two last septa of the shell. 
Stomach (cardiac sac). 
Tentacles (the left one is shown as it was folded in the retracted state, but the “ elbow ” 
is turned outwards and downwards). 
Ventral beak. 
Visceral nerve going to heart and branchiae. 
Passage connecting the right and left divisions of the viscero-pericardial cavity. 
. The inner face of the brachia of the right side. 
Base of corresponding left braehium. 
