ftl 
TROCHUS duplicatus. 
TAB, CLXXXL — Fig. 6. 
Spec. Char. Conical * sides of the whorls concave ; 
a double deeply drenulated carina round the 
base ; umbilicus open, with a tuberctilated 
margin ; aperture quadrangular. 
The upper edge of each whorl is crenulated as well a^ 
the carinae : the concave space between the two edges is 
plain ; the whole surface is shining. The umbilicus, 
which has about seven tubercles around it, forms a strong 
and remarkable character. 
From Little Sudbury* along with the last. 
TROCHUS dimidiatus. 
TAB. CLXXXI.--- JYg. 4. 
Spec. Char. Conical ; base convex, with a carL 
nated margin ; upper part of the whorl con- 
cave, with an entire carina in the middle ; 
aperture pentangular. 
T he smaller whorls are convex ; the last formed 
ones only shew the carinae and concave spaces between 
them : the carina in the middle of the upper part of the 
whorl projects so much as to give the shell a square 
clumsy form : the columella is direct and solid. 
I have received a single example of this from Little 
Sodbury, along with the two latter species : it is dull and 
rather rough on the surface. 
