EXPLANATION OP TERMS. 
xxiv 
Reluse. Bending a little backwards. 
Revolute. Folded or rolled a little outwards. 
SemitTa?isparent. Not perfectly transparent, nor quite opake* 
Senate. Notched like the teeth of a saw. 
Sputulate. Shaped like a spatula or battledore. 
Species. The individual of a family or genus, and distin¬ 
guished from all others of its tribe by permanent marks, called 
spectfic characters. 
Sp'.re.' The body of a shell which consists of separate turns 
or volutions connected by a spiral line. In this work it is used 
for the separate and several volutions themselves. 
Str-.cc. Fine poncave or raised lines. 
Stnate , Furnished with stria: or fine lines. 
Sub . In composition means inclining to, but not quite d*- 
stinctly marked ; as subopake means almost opake ; subeyhn- 
drical, somewhat or nearly cylindrical. 
Subulate . Tapering to a very fine point, like 2n awl. 
Summits. The points above the hinges in bivalve shells: the 
beaks. 
Synonym , Synonymous. Names applied by different authors 
to the same thing: as the Cardium rubrum of Montagu is a 
synonym or synonymous with ourTellina rubra. 
Testaceous. Consisting of shelly matter : composed of the 
materials which form shells. 
Transverse. Marks which run across the shell, or from one 
side to the other; in opposition to longitudinal ones. 
Truncate. Appearing as if abruptly cut ofF. 
Tubercfed. Covered with small wart-like knobs or protu, 
berances. r 
Tubular. Perforated all through, and open at both ends. 
Tumid. Swelling or bulging out 
Umbilicate . Furnished with a hollow indentation or perfo¬ 
ration. 1 " 
Undulate. Proceeding in an irregular or wave- like line. 
U-iivalve. Consisting of a single valve or piece. 
Valves. The several compartments or pieces of which the 
whole shell is composed. 
returns. The distinct turns of a spire, each of which is 
denned by the line of separation orjunction. 
IVhirl . The same as volution. 
