426 PYRAMIDELLID ZA. 
front; it issues from the tentacular membrane, and is placed 
between it and the foot, and is of greater length; on the 
march it is carried in advance of the foot, but the tentacula 
always reach beyond the rostrum, which only very rarely, by 
an extraordmary exertion, is extended to the tentacula: I 
mention this because I have seen the animal figured with the 
rostrum as long as the tentacula, which is an unusual 
position. The tentacula occupy the extent of the membrane 
from which they originate, coalescing at their bases, and 
diverging greatly to their pomts; they are short, flat, broad, 
bevelled, triangular, blunt, setose, with a snow-white line from 
base to point, and a round intense flake-white dot at their 
tips, which give them the aspect of being clavate ; the eyes 
are large, black, placed on the skin at the internal bases of 
the tentacular bifurcation, beneath which is the proboscidal 
orifice. The foot is slightly auricled, and sinuated on each 
side so as to make a gradual central indentation; it is rather 
broad, perfectly round posteally at half extension, but m full 
march it tapers to a moderately pointed lanceolate termina- 
tion, carrying on a plain upper lobe a suboval, light corneous, 
finely striated, simple operculum. 
The animal is active, and shows its peculiarities sans facon. 
It inhabits at Exmouth the coralline, laminarian, and the 
lowest littoral levels. It scarcely differs from C. rissoides, 
except in being white instead of speckled with yellow, and in 
the foot being sinuated in front instead of truncate. There 
is usually a fold on the pillar. 
Cu. 1ntTeRstTINcTA, Mont. 
Odostomia interstincta, Brit. Moll. iii. p. 296, pl. 97. f. 1. 
Animal inhabiting a closely plicated white shell of five and 
a half flattish volutions, the body not being half the length of 
the shell; the apex is less reflexed than usual; the aperture 
has generally a visible tooth, and there are one or two rows 
of crenze or lattice-work on the base, between the ribs, of the 
three lower volutions. The general colour of the animal, as 
regards the portion contamed in the body whorl, is a frosted, 
