242 ZOOLOGY. 
in this species. The mouth is situated in front of the foot 
and at the base of the head-lobe, and is bounded by large puck- 
ered swollen lips. Cutting down from between the tentacles, 
a large buccal mass, the pharynx, is exposed. The mouth- 
cavity is roofed with two broad quadrant-shaped, flat thin 
teeth, with the free-edge serrated. On the floor of the 
mouth lies the ‘‘tongue,” or lingual ribbon (Odontophore), 
which is folded once on itself, and is a thin band composed 
of seven rows of teeth, those forming the two outer rows 
long and much curved, those of the central row being stout: 
and three-toothed. The long slender esophagus is tied 
down, near its middle, by the brain (supracesophageal gan- 
glion); just behind and beneath which are the two large 
salivary glands. The cesophagus suddenly dilates into a 
large stomach-like pouch, which is much larger in this 
species than in other forms allied to it. It is a sort of crop 
or proventriculus (the organ of Delle Chiaje), and rarely oc- 
curs in the Gastropods. On laying it open, it may be seen 
to be spongy at its anterior end, and posteriorly divided by 
numerous transverse partitions into small cavities. The 
cesophagus beyond it is again slender, and leads to the 
stomach situated in the apex of the shell, partly embedded 
in the liver-mass which lies mainly beyond it. From 
the stomach the intestine returns to the head, widely dilat- 
ing into a large sacculated cloaca, before the free up- 
turned vent, which is situated on the right side behind and 
to the right of the right tentacle. The nervous system is 
represented by a pair of large ganglia, forming the brain 
(supracesophageal ganglia) situated just below and behind 
the pharynx. The two other ganglia were not traced, but as 
arule in all Cephalophora there are three pairs of ganglia, 
i. e., the brain (supracesophageal ganglia) with commissures 
passing around the gullet to the pedal or infracesophageal 
ganglia, thus forming the esophageal nervous ring, while the 
visceral or parieto-splanchnic ganglia are placed at a varying 
distance behind the head. 
The heart, contained in its pericardial sac, and consisting of 
a ventricle and auricle, is situated near the posterior end of 
the gills. The latter are disclosed by laying aside the man- 
