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specimen, though not the largest, of a dark ochre colour, 
as found in the Essex and Suffolk craig pits, and peculiar 
to them. The next figure in proportion is of a lighter 
colour, and is from among many choice specimens with 
which I was favoured by Mrs. Cobbold, from the pit on 
the Holywell estate near Ipswich.. The small smooth shell at 
the bottom of the plate is from the same place, and much 
resembles the young recent shells in the irregular swellings 
of the spire. This shell sometimes so nearly resembles 
Murex contrarius, that it has frequently been considered as 
a variety of that, having the mouth on the right, instead of 
the left hand side, and is thought very rare. I have them 
from the smallest to the largest size, selected in pairs, which 
often renders it really doubtful. It is rather remarkable that 
the mouths of the shells have a white almost chalky lining. 
