írtii.
120 MOLLUSCOUS ANIMALS.
P l e u r o t o m a c r y p t o r r a p h e , í . 3 4 . / . 8 . Sow. Tank. C a t.A p p .x iv .
Murex and Pleurotoma bicarinata. Wood, Cat. Suppl. t. 5 , f . 7.
Shell turreted, brown ; spire subulate, nearly twice as long as the mouth ; whorls convex, acutely
ke e led, with an impression close to the suture, and the lakt whorls with several keeled ridges in front.
Mouth ovate ; canal n ot so long as the mouth, tortuous, and slightly umbilicated. Axis 2 inches, 9 lin e s ;
diam. 9 lines.
P l e u r o t o m a c i n g u l i f e r a , t. 34. / . 1. Lam. H is t. vii. 94.
Shell subula te , turre ted, white, minutely brown d o tted , the dots sometimes forming cross w av e s ; the
whorls rounded, convex, finely spirally striated, front of the up p e r with two, and o f the last with four or five
angular ridges, the h inde r part with a convex rounded ridge marked with square reddish spots, formed of three
raised ridges ; the suture d eeply impressed. The m oulh ovate, o b lo n g ; the canal short, rather wide, recurved,
th e slit rather wide, placed on the angular ridge. Axis 2 i in c h e s ; diam. i inch.
I t is much to be regretted tha t M r. Wood should have altered in his Supplement the names given to this
an d other species, especially where the figures were taken from the specimens in the Museum, which were
named as far as possible after their original describer.
P leurotom a a l b i n a , t. 3 4 . / . 4. Lam. Hist. vii. 96.
Shell fusiform, turre ted, white ; whorls with ra the r unequal slightly raised spiral ridges, with fine spiral
lines between them, and angularly keeled behind, the angular ridge with quadrate brown spots, each formed
o f three brown raised lines. The mouth ovate, lanceolate ; the canal slender, cylindrical, rather shorter than
the spire, the slit deep, placed on the angular ridge. Axis 2 inche s; diam. | inch.
This shell agrees with P . cingulife ra in the square spots on the keel, b u t diflfers in the canal being
elongated.
P l e u r o t o m a t u b e r c u l a t a .
Shell fusiform, turre ted, white, brown sp otted, tu b e rcu la r; spire elongated, s len d e r; whorls with a
posterior groove, and spiral series of rounded tubercles, the last with from eight to ten distant beaded spiral
ridges, those o f the canal least beaded. Mouth ovate, with a deep wide sub-posterior n o tc h ; canal elongated,
straight. Axis 16 lines.
Inhab.
B U C C IN ID ^ .
CASSIS.
The foot oblong, moderate sized. T ru n k rather short, cylindrical, ringed. The tentacles short, conical,
on the sides of the base o f the trunk, with the eyes placed ne a r the outer side o f their base.
The operculum varies with the species which I have examined. In Cassis B e zo a r it is ha lf ovate, thin
horny, smooth, r e d ; crown concentrically ringed, with the nucleus placed in the centre near the margin
o f the straight side, which is bent u p and slightly thickened. In Cassis a chatina the operculum is oblong,
with the inne r side rather convex, the outer surface deeply radiately grooved, and the outer rounded edge
deeply crenated, rounder behind, and rather acute in front.
The Queen Conch, and probably all the species which have narrow mouths, has a narrow oblong
operculum, n ot more than one-third the length of the mouth.
Piale X X X r ^
II