139 
TROCHUS Gibsi 
TAR, CCLXXVIIL— Fig. L 
Spec. Char. Conical, short, umbilicated ; sides 
straight ; edge obtusely carinated ; base con- 
vex, reticulato-striated ; in the centre of the 
upper part of the whorls is an elevated band 
crossed by curved strise ; aperture rtiomboidal. 
T his shell is wider than it is high : the upper part is 
smooth, except the concentric band, upon which are 
semicircular striae, indicating a sinus in the outer lip. 
The umbilicus is large, and nearly smooth ; and although 
the inner lip of the mouth is a little reflected over the 
columella, which is thin, it has no tendency to close it. 
A cast in pyritiferous Clay mixed with Sand ; found 
at Folkstone. This and several other shells, hitherto 
called Trochi, with the band around the spire, may more 
properly belong to the genus Pleurotomaria, which I 
may be induced at some future period to adopt. I have 
named this after Mr. Gibs, well known for many years 
as a worthy assistant to several collections of British 
shells. 
