160 Records of the Indian Museum. (VoL. XI, 
to supply this portion of the alimentary canal. It gives off a fine 
nerve to the salivary gland. 
(iii) Viscero-pleural ganglia.—The nerves (VP I-5) are:— 
(1) Two stout nerves arising side by side from the outer 
side. The outer one can be traced to the V-shaped 
process at the anterior end of the foot of the same 
side. ‘The inner one seems to supply the anterior end 
of the foot. These two nerves arise from the oval 
eroup of ganglionic cells on the outer and anterior 
portion of the ganglia. 
(2) A fine nerve arising from the outer aspect of the left 
ganglion at its posterior end. It passes along the 
gullet and ends in the liver a little behind the 
antero-inferior surface of the liver. 
(3) A nerve from the right ganglion which supplies the fe- 
male genital organs. : 
(4) A fine nerve from the right ganglion to the penis, penial 
sheath and the simrothian gland. 
(5) Nerves to the side of the mouth above the pedal groove 
(VP 5). 
(iv) Pedal ganglia (P 1-3).—The nerves are :— 
(1) A nerve to the pedal giand. 
(2) Nerves to the lateral wall of the mantle just above the 
groove round the foot. 
(3) The long pedal cord which passes backwards along the 
dorsal surface of the foot to its posterior end. It 
gives off numerous nerves from its outer side to 
supply the foot. 
VI. Eyes and Head Appendages. 
The eyes are of rhipidoglossate type. Each forms a vesicle 
which is closed anteriorly forming a cornea composed of an exter- 
nal layer of epithelial cells, continuous with the tegumentary 
epithelium, an internal layer of epithelial cells (continuous with 
retina) and an intervening layer of transparent connective tissue. 
There is an oval crystalline lens with a surrounding layer of 
vitreous humour. 
Ommatophore.—The cylindrical body of the ommatophores is 
hollow with a thick wall. Just behind the optic vesicle is a thin 
septum of connective tissue stretching transversely across the 
cavity. The wall consists of the following layers :— 
(1) A single layer of cubical epithelium on the outer side. 
(2) A thick layer of connective tissue with numerous cells. 
This layer contains some mucous glands placed at 
distant intervals, ‘There are numerous pigment gra- 
nules along the course of the connective tissue fibres. 
(3) A layer of circular muscle fibres with a few radial fibres 
from the next internal coat. 
(4) A layer of longitudinal muscle fibres. 
