PART I.— ZOOLOGY. 
21 
Tables 8 — 11. The genera allied to Buccinum. 
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 ( Cyathura ). 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 10. 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. The mulberry shells, (J 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 Purpuroe; 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 qnimal to keep its body level 
with the surface of the growing coral that it may be enabled to procure 
its food. The Litiopce which, continually floating about the ocean, are 
attached to the Gulph weed. The whelks {Buccinum). The needle 
shell ( Terebra). The Bullia , which has a very large animal for 
the size of the shell. 
Table 11. The Nassa. The JRingicula, which has been con- 
founded with the Auricula , but only differs from the Nassce in 
having the large plaits on the pillar. The Olives , Annularia , and 
butter shells, or Eburna, which are polished externally : as the 
camp olive, ( Oliva porphyria ,) from Panama; the Brazilian olive 
( O. Brasiliensis). 
Tables 12 — 14. The genera allied to the Volutes. 
Table 12. The Melons, or Cymbium, which often grow to a large 
size, and are used for domestic purposes by the Chinese and other 
Asiatic nations : as the crowned melon, and some of the Volutes. 
The young of the melons are produced alive and of a large size, the 
top of the spine is of an irregular shape like a nipple. 
Table 13. The Volutes; as the very rare courtier or red clouded 
volute ( V. aulica) ; the gambaroon ( Voluta Beckii) ; the imperial vo- 
lute ( V. imperialis), from China ; long-spined volute ( V. ancilla), 
from the Falkland Islands. 
