GALLERY.] 
NATURAL HISTORY. 
The family of Volutes (Volutux®, Cases 12—14) have a recurved 
syphon, and only a nick in the front of the mouth of the shell, like 
some of the former genera; but the front of the pillar of the shell is 
regularly and obliquely plaited. The foot of the animal is very large, 
partly hiding the shell, and generally deeply nicked on each side in 
front. In general the shell is covered with a distinct periostraca, as 
Mitra, Voluta , and Musica , but in a few, as Cymbium, the animal 
when any sand or other matter gets between the shell and the upper 
surface of its foot, secretes a quantity of shelly matter, and covers the 
adventitious substance with a glassy coat, so as to prevent the extraneous 
particles from irritating it. In some, as Voluta angulata K one of the 
sides, and in others, as Marginella , both sides of the mantle^ &re~pr€K > ' 
duced and reflected over the back of the shell, and the shelly matter 
secreted by these parts covers the outer surface of the shell with a 
polished coat, like the cowries. Only a few species, as Voluta musica, 
and some of the smaller Mitres, are provided with a horny operculum, 
which is entirely deficient in the other kinds. The animals of the 
genus Cymbium are ovoviviparous ; the shell of the newly bora animal 
is very large, and the apex of the spire of many of these shells is very 
irregularly twisted. The Vulpe cula differ from Mitra in the outer 
lip being striated within. The Imbricaria are obconic shells w'ith a 
linear mouth and many plaits on the pillar. The Hyalines differ from 
the Marginella in the spire being short and the outer lip only slightly 
thickened; and the Persiculce in the outer lip not being thickened ex¬ 
ternally, and in the inner lip being cross grooved. 
The family of Cowries (C YPRJEADiE, Cases 15, 16) in the young 
state have a thin shell, covered with a thin periostraca, and with a wide 
mouth like that of Bulla, but, as they approach the adult age, the lobe 
of the mantle spreads out so as to cover the back of the shell with two 
large lobes, which are capable of being contracted into the cavity of the 
shell at will; at the same time the mouth of the shell is gradually con¬ 
tracted and inflexed, only leaving a narrow slit, and its back is covered 
with an enamel coat, deposited on its sides by the lobes of the mantle ; 
the foot is rather small. The outer surface and edge of the lobes of 
the mantle are generally covered with various shaped and often branched 
beards. In Cypraa, Luponia, and Ovula, the outer coat of the shell 
is polished, but in Cyprovula and Trivia it is covered with raised ribs. 
In most of the genera both the lips are plaited, but in Ovula the inner 
one is smooth. They are said to live on sealants under rocks near the 
breakers ; they walk rapidly, but expand and contract their mantle very 
slowly. The Luponia differ from the Cypraa, the front of the inner lip 
being irregularly plaited. The Erato chiefly differs from the Trivia in 
the shell being obconical with a conical and exposed spire; some of them 
are smooth like the Marginella, from which they are easily known by the 
absence of the fold on the pillar, but some are ribbed across externally 
like the Trivia. The Calpurni differ from the Ovula in having a 
tubercle on each side, and the shuttles ( radius ) in the canal being ex¬ 
tended at each end of the mouth. 
Near this family must be placed, for the present, the anomalous 
genus Coriocella, (Case 16,) which is peculiar among these animals for 
having a thin, white, ear-like shell, imbedded in the large expanded 
coriaceous mantle, wdiich is nicked in front for the syphon. They are 
