NOMENCLATURE. 
23 
spiralis. Spiral ; so twisted that an imaginary 
plane passing through the middle of the 
outer whorl shall bisect all the others, or 
divide them into two equal parts. 
tiirrita. Turreted ; the whorls gradually attenu- 
ating or decreasing in the form of a cone ; 
the length of these shells always consider- 
ably exceeds their width. 
turhinata. Turbinate ; the belly swelling or tu- 
mid ; the spire comparatively small, rising 
as it were from the hollow of the body. 
imbilicata. Umbilicate ; possessing an umbili- 
cus. 
Varices. Varices; longitudinal gibbous su- 
tures formed in the growth of the shell 
at certain proportionable distances on the 
whorls. 
contimiati. Continuous ; running through all the 
whorls. 
decussati. Decussate ; longitudinally and trans- 
versely divided or crossed. 
scrobiculati. Scrobiculate ; engraven with cavi- 
ties towards the margins. 
