Norwich Castle Museum. 111 
to several families, with one of which, that of the 
Ammonites, we are very familiar. Of all these 
numerous forms that of JVau/z/us is the only one 
remaining ; this fact alone should invest the creature 
with surpassing interest, for in it we behold an animal 
of very ancient descent, left as it were to form a key 
to the structure and habits of its brethren of the 
Carboniferous and Jurassic periods. 
Class II. consists of the GASTEROPODA, 
containing a very large number of orders and species, 
of which our common Garden Snail may be taken as 
a familiar example. The visitor will be sure to be 
attracted by the well-known form of Strombus gigas, 
the Indian fountain shell, immense quantities of which 
are annually imported from the Bahamas for the 
manufacture of cameos; it is said to be a favourite 
article of food with the natives of Barbadoes, and to 
be used for the manufacture of various articles useful 
and ornamental wherever found. TZ77/on variegatum 
is also a fine shell. This is the Conch shell, used as a 
trumpet by the natives of the southern seas, and a 
specimen will be seen in the collection perforated in 
the side for that purpose. Some singular shells of the 
genus Murex are remarkable for their development 
of spines ; they are all carnivorous, and furnished with 
a long proboscis, at the end of which 1s.a spiny tongue, 
with which they bore through the shells of other 
species and devour their soft parts. From certain 
species of A/urex found in the Mediterranean the 
ancients obtained their purple dye. The genus 
Terebra, known from the long pointed form of the 
shell as the ‘ Augur Shell,” will attract attention by 
their singular long drawn-out whorls, as also Purpura, 
a mollusc of wide distribution, one species of which 
is common on the British coast at low water, and is 
very destructive to mussel-beds; it produces a dull 
