GALLERY.] 
NATURAL HISTORY. 
•27 
the reversed spindle shell, of the reversed buHmus, or of physos or clau- 
siliae, with the whorls in the common direction, would be as rare and 
valuable as reversed shells of those kinds which are generally of the 
common direction. The large Chinese spindle shell, which grows to a 
large size. 
Tables 7, 8. The Turnip Shells ( Turhinella), some kinds of which 
are very large and heavy. The}^ are generally spotted when young 
and white when adult, and from their form have been called Turnip 
Shells or Rape Shells; these are often used as oil vessels in the Indian 
temples, and for this purpose are carved and otherwise ornamented, 
as may be seen by some in the collection. When reversed they are 
much sought for by the Ceylonese, and highly valued ; one of these 
reversed clamp shells is in the collection ; they are said to sell for a ve 
large price in Ceylon and China. The Iris wave, ( TurhineJla pris- 
matica,) so called, because when the shell is wetted the periostraca 
gives out brilliant prismatic reflections. The tulip shells, (Fasciolaria,') 
among which is a kind which is by far larger than any other univalve 
shell yet discovered. The ostrich foot, (^Struthiolaria,) and the 
pelican’s foot, (Aporrhais .) 
Tables 8—11. The genera allied to Succinum. 
Table 8. The helmet shells, ( Cassis,') some of which grow to a very 
large size, and are used to form cameos. 
Table 9. The Cassidea. The false helmet ( Cassidaria). The 
harp helmet ( Oyaif/mra). The tun, which are often used 
in tropical climates to bale boats with. And the harps, (Ilarpa,) so 
called because the ribs left on the surface by each succeeding addition 
to the growth of the shell have been compared to the strings of a harp. 
In some species these ribs are far apart, in others close; the latter are called 
the double-stringed or ridged harp, they were formerly very rare. 
Table 10. The purple shell, {Purpura,) so called because, like 
many oth^r of the animals of this kind, they emit a purple secretion 
which has been used in dyeing. The unicorn shell, {Monoceros,) 
so called because of the tooth-like horn on the front of the edge of the 
outer lip. The planaxis, which has been confounded with the peri¬ 
winkles. The limpet purple, ( Concholepas,) which was formerly ar¬ 
ranged with the Patella, because of the large size of the mouth of its 
shells. It exactly resembles the valve of the heart cockle, a bivalve 
shell, in shape, but it has the sam.e small horn-like projection on the front 
of the outer lip. The mulberry shells, {Ricinula,) which are usually 
covered with spines, and have been thought to resemble the fruit. The 
Magillus, which, when the shell was first discovered, was thought 
by Guetard to be a stalactite, or mineral secretion; more lately 
Lamarck placed it with the worm shells, but the animal scarcely 
differs from the Purpura;,- when the animal is young it has a thin 
shell of nearly the usual form, but of a white colour ; -at a certain 
period of its growth, the anim.al deposits in the cavity such a quantity of 
calcareous matter as to produce the shell, in its subsequent growth, into 
a more or less elongated straight process, leaving only a small cavity 
for the body of the animal at its end. They exist in or on corals, and 
the extension of the shell is to allow the animal to keep its body level 
with the surface of the growing coral, that it may be enabled to procure 
its food. The Litiopee, which, continually floating about the ocean, are 
c 2 
