Pvn H,i I'UitlS

GASTRANA. 369
in the newer tertiary strata of the sonth of Italy.
This
species being common in some parts of the west of Ireland
which have been often explored by many of our
best zoologists, it is surprising that the animal has not
been noticed bv any writer on the British or Irish Mollusca,
and that it should have devolved on a German
conchologist
to examine it on the distant shores of
Sicily, and on a French savant to investigate
its ana-
tomy in North Africa. Their descriptions, however,
differ from that of Poli, as well as among themselves.
According to Philippi the siphonal orifices are not cirrous
; the characters of the animal which I have quoted
from Deshayes give the number of cirri which surround
the aperture of each tube ; while Poli states that the
cirri encircling the branchial tube are scarcely perceptible,
even by the aid of a lens, and that the mouth of the
other tube is plain. The lesser tooth in the left valve
is thrown into the shade by its huge companion, and
the genus is represented by authors as having only one
tooth in that valve. Montagu says
that his Tellina
polygona has, " besides the very large, triangular, bifid
tooth, an approximate small one, that might easily be
passed unnoticed." I believe that shell was only a
half-grown and distorted G. fragilis ; I have one exactly
answering to the particulars and figure given in the
( Testacea Britannica/ The young are more oval, and
not so inequilateral.
A specimen in my collection con-
tains a small incipient pearl close to the posterior scar.
The regularity of sculpture varies in individuals from
different localities.
It is the Tellina striatula of Olivi, T. jugosa of Brown,
Petricola lamellosa and P. ochroleuca of Lamarck, and
(in its younger or immature state) his Psammotcea
tarentina.
r 5