96 THE LAND SNAILS 
Apex, a, is the beginning of the spire, or the part 
first formed. : 
Base, is that region of the shell opposite the apex. 
A shell rests on its base, when the apex is uppermost. 
Suture, s, is the seam, or line of division between the 
whorls. : 
Umbilicus, u, is a cavity left in the central axis of the 
shell, around which the whorls revolve. The umbilicus is 
seen from the base of the shell. The umbilicus is said to 
be open when a distinct perforation appears in the base 
of the shell; closed, when a portion of the lip extends 
over it, (as in the adult condition of the shells of many 
species), and absent, when the whorls revolve so a 
as to leave no central space. 
Lip, l, is the border of the aperture. When the edge 
of the aperture is sharp, the lip is said to be simple. — 
When produced into a flange, it is called a reflected lip- 
The columella is that portion of the aperture nearest the — 
centre of the shell. 
Strie, st, or lines of growth, are minute lines, noni 
parallel with the border of the aperture, and indicate the 
successive enlargements of the shell. 
Nearly all shells have an outer coating of animal mat- 
ter, called the epidermis. After the death of the animal 
- this coating soon loses its color, and wears away, leaving 
the shell faded and bleached. : 
Heux ALBOLABRIS Say. The general description of this 
. n in our first number need not be repeat 
