MOLLUSCOUS A N IM A L S . 121
P E R SO N A .
The foot very large, expanded, forming the expanded base round the mouth as in CatsU. The internal
varices are permanent, as^in th a t genus, and the pilla r is very tortuous, with two very strong plaits in front—
the front one is longest, and irregularly to o th ed ; the cavities o f the u p p e r whorls are q u ite filled u p , and the
cavities o f the succeeding ones are furnished internally w ith concave shelly septa.
These shells have generally been placed with T r ito n , b ut they differ from them in the large size o f the
foot of the animal, and the expanded base and permanent varices in the shell. They agree in the ir resem-
blance in the shell and mouth to tha t genus.
CA SS ID ARIA .
The foot is small, oval, folded across. The proboscis cylindrical, conical, long, slender. The tentacles
subulate, thick, placed on the sides of the base of th e proboscis, with the eyes on the outer side o f their base.
The male organ la rge ; the respiratory c anal ra the r short. Tlie operculum is oblong, large, horny, solid, nearly
straight on one side, and rather narrow in front, like tha t of Bu c c in um in shape.
C a s s i d a r i a a c u t a .
Shell ovate, fusiform, ventricose, white (with two or three brown spira l b an d s); spire conical, a c u te ;
whorls longitudinally transversely ribbed, subnodula r, with an acutely angular subposterior r id g e ; outer lip
thickened externally, ten o r twelve toothed internally, inne r lip slightly raised, with ra th e r d istan t cross
ridges.
DOL IUM.
The foot very large, expanded, n ot folded, rounded behind, without any operculum. The proboscis very
long, snbcylindrical, tobular, situated in a deep cavity, ou the edge of which are placed the tentacles. The
tentacles subulate, p laced on each side o f the base of the tru n k , and with the eyes placed on short tubercles a t
Iheir outer base. The male organ is very large, and like tha t o f Bnc c inum umdatnm in sh a p e ; respiratory
c anal short.
I have b een enabled to examine the m ale o f B . Pmnum and two females o f z>. P e rd ix . In the former the
proboscis is elongated, conical, and in the la tte r it is very large and trumpet-shaped, w ith a short exposed
hooked tongue on the top. The three specimens o f D . PomMwi v aried in the ir tenta c le s; one had both the
tentacles perfect, one had no tentacle on the right side, ils place being occupied by the penis, a nd th e last
had none on the left, b u t a targe one on the right side before the male organ. Atl the specimens o f the other
species being female, I could not observe w hether it was liable to simitar v ariations.
H A R PA .
The foot very large, expanded, nicked even with the head on each side in front, and produced and
keeled above behind, without any operculum. The edge of the mantle is thin, and not reflexed, and furnished
with a rather large conical respiratory canal. The trunk is long, conical, hard. The tentacles are conical,
thick, rather close together a t th e ii b a s e ; their base is thickened for about one-third o f the ir length, and a t the’
outer tip of the base the eyes are placed. The male organ is large and conical. When alive these animals
are orange-spotted; they live on s an d -b an ls, and are taken with meat attached to lines, o r w ith nets attached
to a rake. They are said only to feed a t sun-rise.
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