i r
MOLLUSCOUS A N IM A L S . 137
N a t i c a q u a d r i f a s c i a t a .
Shell ovate, globose, solid, smooth, chesnut b row n ; spire very short, co n ic a l; la st whorl with four
narrow white spiral bands, hinder one broadest, extending u p the sp ire ; throat purplish ; inner lip large,
black brown. Axis largely umbilicated. Axis \ \ inch.
Inhab.
N a t i c a c r u e n t a t a .
The front o f the foot is produced, tentacles small, on th e edge o f a small cross membrane, with the
mouth in a deep groove below it, between the tenta cula r ridge and the h inde r edge of the front o f the fo o t;
th e penis very large, like tha t o f Buccinum, with a small nearly terminal appendage, retracted into a cavity
placed on the hinder side of the right tentacle. The operculum shelly.
N a t i c a m e l a n o s t o m a .
The operculum with a d istinc t elevated spira l ridge in front. The muscle o f attachment leaves an
gated scar on the pillar.
S IG A R E T U S . Lam. C RY PTOSTOM A. Blain.
T h e animal o f this shell only differs from N a tic a in being much larger in respect to the size o f the
shell, and in being p rovided with only a small ovate horny operculum. The size o f the animal differs in the
various species: thus in S . cóncavas it is c apable o f being withdrawn into the cavity o f the shell, which is not
'•'■'•e with S. haliotoideus.
M ER R IA .
The body sp ira l; the tran k proboscis-like, the tentacles conical, simple, w ith the eyes on th e ir'o u te r base*
the foot small, rounded, with an oblong expansion in front, and a large triangular wing-like lobe on each side •
the edge o f the mantle simple ; the operculum very small, thin, ju s t at the top o f th e foot. The shell white
naked.
The pedal appendages o f this genus are peculiar.
M e r r i a c a n c e l l a t a .
Sigaretus cancellatus. Lam.
N E R IT IN A .
Trunk short, annulate, w ith a short fringe over the head ; a low e le v a to r, ridge on each side o f the body
from the back o f the tentacula to the h inde r p a rt ! the gills lanceolate, free, except a t the base attached to the
ba ck o f the left side of the respiratory cavity, and b en t o .e r towards the tig h t side, formed o f lamina united to
labia. Eyes on short tubercles, free, b u t on the side o f the base of Ihe tentacles ; tentacles conical, separate
vent on the right side o f the branchial cavity. Tbe muscles o f attachment on each end o f the columella large
and oblong. ’ ®
Perhaps this genus on account o f the series of fringe on each side o f the body should rather be placed
the T uM n e s . I t is hermaphrodite like them ! for I have not, in the many specimens I have examined, obse
any with the male organ exserted.
The lamina which separates the u p p e r whorls of these shells is ab so rb e d ; the mantle o f N . Corona
(when preserved in spirits) does not exhibit any process b y which it forms the series o f tubula r spines.
Several of the species live a long while o ut o f water.
near
obsen-ed