38 
NATURAL HISTORY. 
[EAST. ZOOL. 
shells are always very valuable, but this is not the case. A specimen of 
the reversed spindle shell, of the reversed bulimus, or of physae 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. The Turnip Shells ( Turbinella ), some kinds of which are 
very large and heavy. They 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 very 
large price in Ceylon and China. The Iris wave ( Turbinella 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 7—11. The genera allied to JBuccinum . 
Tables 7, 8. The helmet shells ( Cassis ), some of which grow to a 
very large size, and are used to form cameos. The Cassidea. The 
false helmet ( Cassidaria ). The harp helmet ( Cyathara ). The tun 
(Dolium ), which are often used in tropical climates to bale boats 
with. And the harps ( Harpa ), 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 9. The purple shell ( Purpura ), so called because, like 
many other 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 left valve of the heart cockle, a 
bivalve shell, in shape, but it has the same small horn-like projection on 
the front of the outer lip. "’"he mulberry shells ( Ricinula ), which 
are usually covered with spines, and have been thought to resemble the 
fruit. 
Table 10. The Magilus , 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 Purpurce; 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 animal 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 
