NOMENCLATURE. 23 



Spiralis. Spiral ; so twisted that an imaginary 

 plane passing through the middle of the 

 outer whorl shall bisect ail the others, or 

 divide them into two equal parts. 



turrita. Turreted ; tlie whorls gradually attenu- 

 ating or decreasing in the form of a cone : 

 the length of these shells always consider- 

 ably exceeds their width, 



turlinata. Turbinate ; the belly swelling or tu- 

 mid ; the spire comparatively small, rising 

 as it were from the hollow of the body. 



nmlilicata. 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. 



continuati. Continuous ; running through all the 

 whorls. 



decussati. Decussate ; longitudinally and trans- 

 versely divided or crossed. 



scrohiculaii. Scrobiculate ; engraven with cavi- 

 ties towards the margins. 



