282 SIR C. ELIOT AND T. J. EVANS. 
which can be called a head. In some specimens the mouth 
is a simple orifice above the foot, but in others there is a sort 
of snout. It would seem, however, that this protrusion 1s 
due to artificial causes and is not a natural and permanent 
structure. There are no lamelle on the under side of the 
mantle as in Phyllidia, ete., but it is uneven and in some 
cases presents ridges and bulges probably caused by the 
hepatic follicles. The foot is large, with ample expanded 
margins. The anterior margin is straight and not grooved. 
When the internal cavity is opened, the central nervous 
system (fig. 3) is seen lying on the top of the cesophagus and 
surrounding it. ‘There is no trace of a blood-gland. The | 
cerebro-pleural ganglia (fig. 3, a) are rather large and ellipti- 
cal. Externally they show no division but a section indicates 
that the ganglionic mass is of dual origin and divided inter- 
nally by a constriction into two nearly equal ellipsoids. The 
pedal ganglia (fig. 3, b) are also elliptical and lie below and 
rather behind the cerebro-pleural. The buccal ganglia (fig. 
3, d) are rather large, close to the pedal ganglia and also close 
to one another. No gastro-cesophageal ganglia could be found 
and no otocysts. The eyes are black and lie near the base of 
the rhinophores on the olfactory ganglia (fig.3,c), the optic and 
olfactory nerves being apparently fused. This arrangement 
is unusual, but something similar may be seen in Bergh’s 
figure (Malac. Unters. in Semper’s ‘ Reisen,’ Heft. xv, pl. 
Ixxi, fig. 17) of the nervous system of Tritonia (Candiella) 
plebeia where the optic and olfactory nerves are joined for 
a considerable distance and separate only in their upper por- 
tion. The pigment layer of the eye lines a cup formed of a 
few large retinal cells, from which fibres run into the olfac- 
tory nerve at the base of its ganglion. 
The jaws are yellowish but not deeply pigmented in any 
part, moderately convex, not very broad, united at the top by 
a hinge, and provided with short processes. The edge (fig. 4) 
is armed with a row! of very distinct projections with spatu- 
1 In the specimen described by Sir C. Eliot and Mr. Crossland two rows of 
broad denticles were found on the jaws, which were relatively wider, and the 
