PLATE I. 
Spirula peronii, female (Challenger specimen). 
Fig. 1.—Left side. 
Fig. 2.—Ventral side. 
Fig. 3.—Dorsal side. 
Fig. 4.—Posterior or aboral end. 
Fig. 5.—-Dorsal side; the free mantle is cut along the median dorsal line and the 
halves divaricated. 
Fig. 6.—Ventral side, the free mantle laid open in the median line and the lateral 
portion divaricated; moreover, the right wall of the “episoma” is 
removed so as to lay open the right half of the viscero-pericardial cavity. 
In all the figures : 
O 
a, b. remains left by the colouring matter of the irides of the eyes on the 
inner surface of the mantle in consequence apparently of the strong 
contraction upon them. 
an. Anus. 
hr. hr’. Gills. 
d.i. Median dorsal infundibular apophyse (nuchal cartilage). 
E. E'. Eyes. 
F. F'. Fins. 
fs. Terminal fossa and papilla. 
I.c. Collar of the infundibulum. 
ik. Ink bag. 
I.v. 
li. li'. 
ng. ng'. 
ol. oV. 
o.m. 
o.d. 
pb. pb'. 
P. F. 
P.cl. PI PI. 
Infundibular valve. 
Right and left infundibular apophyses. 
Nidamental glands. 
Olfactory organs. 
Mass of the ovary. 
Oviduct. 
Palliobranchial ligaments. 
Mantle. 
Dorsal and lateral lobes of the free edges of the mantle. 
Sh. Shell seen through the ventral and dorsal openings. 
T. T . Tentacular arms. 
x. Accessory nidamental glands. 
I, II, III, IV, I', II', IIP, IV', brachia. 
