19 
N ATICA, Lamarcke. 
wie Cuar. Univalve, nearly globose umbilicated 
shell ; aperture entire, semi-orbicular ; columella 
transverse, without teeth, externally callous, 
callosity contracting, and sometimes even cover- 
ing the umbilicus. 
NATICA glaucinoides. 
TAB. V.—Three upper figures. 
Spec. Cuar. Nearly globose, spire rather elongated ; 
umbilicus simple, partly covered ; upper part of 
each whorle slightly depressed. 
mm 
Wouortes about five, the breadth of the lowest volution 
three-fourths of the length of the shell, the upper part a 
little flattened or even concave, the remainder gibbous. 
Umbilicus large, sometimes with a little appendage from 
the lip, projecting more or less conspicuously over it, and 
forming either a transverse ridge dividing the umbilicus, 
or a callous tooth. Shell externally glossy, of a light 
brown colour with some indications of darker brown bands. 
The remark, that fossil shells differ from the recent ones, 
is here curiously verified. This shell in its general appear- 
ance so much resembles Nerita glaucina, that without 
comparison it was considered as the same species, but on 
observing it with attention it will be found sufficiently 
distinct, the spire in this will be found to be higher, nearly 
in the proportion of one-fourth to one-fifth, than in N. 
Glaucina. N. Canrena is yet shorter. I have seen twenty 
or more specimens all alike. The inner or umbilical lip is 
