102 Beautiful Shells. 
We here give a representation of this shell, and 
also of the shell of the pretty little Pearly Trigonia 
(7. margaritacea), included in the Arcade family ; 
this is a rare species, found only in the seas ot 
New Holland. 
SCALLOP SHELLS. 
Several species of Scallop Shells are found scat- 
tered about on our shores; they belong, as before 
stated, to the family Pectinide, the meaning of 
which term has been already explained. These shells 
were called by Cuvier “ the Butterflies of the Ocean,” 
on account of the various and beautiful colours 
which they exhibit. Some of them are exceedingly 
thin, and brittle as glass; one species found in the 
Arctic regions is as transparent as that substance, 
and is therefore called P. vitreus, from the Latin for 
glass, which is vitrewm. One of the commonest of 
our native Scallops is the St. James’s Cockle (P. 
Jacobeus). This shellis found in great plenty along 
our southern coasts; 1t is often referred to by old 
writers, on account of having been commonly worn 
in the hats of pilgrims to Palestine or the Holy 
