494 Mr. Garner on the Nervous System of Molluscous Animals, 
pharyngeal ganglia (D.) send down distinct filaments to the salivary ducts and 
towards the ganglion on the stomach; the retractor muscles of the pha- 
rynx being supplied with nerves (g.) from a point close to those which arise 
to form them (in these animals midway. between the superior and inferior 
portions). We shall see in Cephalopoda that the pharyngeal ganglia through 
the labial receive a filament both from the superior and inferior portions of 
the ring; and in Gasteropoda it may often also be noticed that a filament 
runs back from the labial nerves (7.) to the nerve forming the pharyngeal 
ganglia. The nerves of the eye, tentacles and lips are given off, as usual, on 
each side superiorly, the part where they arise being sometimes more or less 
swollen into a ganglion on the ring. 
In Natica (Tas. XXVI. fig. 6.), Buccinum (fig. 1, 2 &3.), Purpura (fig. 10.), 
Murex, Mitra (fig. 11.), Columbella* (fig. 12.), and Oliva (fig. 4 & 5.), all spiral, 
branchiferous, and carnivorous Gasteropoda, the nervous system is very similar 
in all. The brain is still principally subcesophageal, and it presents much 
resemblance to that of the Sepia. From the posterior part the branchio- 
visceral nerves ( f.) arise, generally forming a ganglion or plexus (g.) at the 
back of the thoracic cavity, near the second stomach. The right nerve of the 
mantle (c.) crosses over the cesophagus, a ganglion (H.) being formed on it, 
near the brain, in Buccinum and Purpura. ‘This nerve, and its fellow, whieh 
does not cross under the cesophagus, supply the margin of the branchial 
cavity and siphon, In Natica the right goes to the left over the cesophagus, 
and the left under it to the right, both forming a ganglion (H.). From the 
anterior part of the inferior portion the nerves of the foot (d.) are derived; also 
in part those of the retractor muscle of the animal into its shell: a few fila- 
ments (^.) arise on each side this part to the sides and integument of the 
neck. The nerves of the lips (7.), eyes, and tentacles (g.) arise as usual; the 
former in part supply the muscles of the proboscis, the other nerves supply- 
ing the organ more anteriorly, being from the pharyngeal nerve. The pharyn- 
geal ganglia (D.) in Purpura and Buccinum are close to the brain, the nerves 
proceeding from them being very long, to allow of the extension of the pro- 
boscis; in /Vafica they are situated as usual on the pharynx, and are con- 
— * The author takes the liberty of introducing figures of Mitra and Columbella, though not bearing 
upon the subject of the paper, because he believes the animals have not been described, 
