NG.12;| H. J. FLEuRE: Anatomy of Melo indicus. 409 
gut. The distal ends of the tubes are much longer than 
the ends which unite. 
Behind the proboscis, the gut lies in the general anterior 
cavity suspended by many fibrous strands. Just behind the 
proboscis is a short section of somewhat increased diameter (Ph. L.., 
pl. xxx, fig. 6) corresponding with the ‘* Pharynx de Leiblein ’’ noted 
by French observers in some other Rhachiglossa Behind this, the 
nerve-collar gathers round the gut, and, some distance behind this, 
the great median or unpaired gland of the fore-gut stands out 
above it. The duct of the latter goes forward in the gut wall and 
opens near the level of the nerve-collar. Bouvier thought the 
gland was usually small in Volutids but large in Melo neptuni 
which he studied. Woodward thought the gland longer in Volutids 
than in the Rhachiglossa in general. Pace founda very large 
gland in V. musica. It is certainly large in M.indécus and the 
other observations make it probable that Woodward is right. 
The oesophagus is continued back as a cylindrical tube which 
widens suddenly at a certain level. The lining of the wider section 
is strongly ribbed by longitudinal folds (pl. xxx, fig. 7a) and this 
section goes back into the visceral mass where it opensinto a stomach 
which is of a U, or, rather, a Y-shape with a caecal outgrowth on 
one side. The digestive gland occupies the upper part of the 
spiral and communicates, so far as I have been able to trace it, 
with the caecal outgrowth of the stomach by two openings (see 
pl. xxx, figs.6—7). Following upon the stomach is the short intes- 
tine overlying the oviduct and wrapped around to a considerable 
extent by the right (or posterior) portion of the excretory organ. 
The anus (pl. xxix, fig. 4, A.) is deeper in the branchial cavity than 
the oviducal opening. Both lie, as already stated, well back on 
the right side and thus out of the way of the ctenidium and osphra- 
dium and the arrangements which, it has been suggested, secure 
the closing of the front margin of the branchial cavity. 
IV.—NERVOUS SysTEM. (Pl. xxxii, figs. 21 and 22). 
The nervous system has been described more thoroughly than 
any other, and Bouvier’s observations are established and con- 
firmed, as usual, by subsequent workers. A detailed account of 
the system is therefore superfluous though reference may be made 
to the interesting question of the supra-intestinal ganglion. 
Cerebral, pleural and pedal ganglia are intimately united in 
pairs and the cerebrals are closely fused with the pleurals to form 
a trapezoidal mass. From this mass are given off, as Bouvier 
found ,— 
(a) Two large nerves to the proboscis on each side. 
(b) Nerves to the fore-roof above the head. 
(c) Nerves to the anterior part of the body wall 
The above are from the cerebral ganglia. 
(d) Parietal nerves from the pleural ganglia. 
