182 
Prof. F. W. Hutton on the 
retracted, and are occasionally emarginate at the apex. I 
should also call the colour of the head-lobes, and the parts of 
the mantle hidden by the shell, blackish purple, and not dark 
brown. 
The pulmonary cavity is large, ciliated, and completely 
closed in front; the opening is on the right side close to the 
anus (tig. 1, «, and 8, a). The principal opening is in front of 
the anus; but it is continued as a narrow slit above and behind 
it. Lying transversely on the roof of the cavity is a large, 
pale yellow, pectinate renal organ (fig. 2,/), which opens out¬ 
wards at its apex on the right side above the pulmonary 
opening. This organ contains large quantities of loosely 
aggregated colourless spherical cells, from '0003 to '00075 
inch in diameter, containing dark nuclei, similar to those found 
in this organ in other pulmonates. Two muscular slips, one 
of which divides into several portions, arise from the base of 
the columellar muscle, and are inserted into the roof of the 
pulmonary cavity. 
The heart lies in the left anterior corner of the pulmonary 
cavity, close to the base, or broadest end, of the renal organ 
(fig. 2, g, and 3, n). The ventricle is yellow in colour and 
pyriform in shape, the larger end being turned to the auricle, 
which receives the blood from the renal organ. The ventricle 
is posterior to the auricle. The aorta soon divides ; but I have 
not been able to trace out the circulatory system. The large 
vein (?), described by Quoy and Gaimard as lying on the 
roof of the pulmonary cavity, alongside the rectum, is plainly 
visible; but I have not succeeded in tracing its connexions. 
It certainly does not proceed from the heart in the way shown 
by Quoy and Gaimard’s figure. 
Throughout the whole animal, but especially on the oviduct, 
the connective tissue secretes oval calcareous granules, formed 
of concentric layers, which much resemble in appearance 
grains of wheat-starch (fig. 14). These granules do not de¬ 
polarize light. 
The mouth is soft, without any horny jaws. The buccal 
mass (fig. 3, a, and 4) is not large. The odontophore (fig. 5) 
is spathulate, with transverse rows of about thirty teeth. Each 
transverse row consists of a single median (or rachis) tooth, 
with about fourteen laterals on each side. The rachis-teeth 
(fig. 7) are blunt, bilobed at the base, and with two or three 
small cusps or denticulations on each side. The lateral teeth 
(fig. 6) are simple, strong, and curved, the apex being rather 
blunt; they are placed so that the convex side of each tooth 
lies inwards. The orbis radulse is toothless; the anterior 
transverse rows form a double curve, the rachis-tooth occupy- 
