Pvn H,i I'UitlS

96 aviculid^:.
and the opposite ones from six to ten times as long in full-
grown specimens : hinge-line very long : ligament broad, sepa-
rating the beaks, so as to form a rather wide area : hinge-plate
thick, strong, and ronnded : teeth consisting
of a blunt tubercle
a little in front of and below the
in the upper valve, placed
hinge, and a double tooth in the other valve, into which the
tubercular tooth locks: inside highly and beautifully irides-
cent, marked with faint and irregular grooves which diverge
that of the
from the beaks : muscular scars distinct, especially
posterior
Habitat :
adductor. L. 3. B. 1*65.
the trawlers
Plymouth offing, procured by
in 20-25 fathoms, sometimes attached to species of
Gorgonia
and Sertularia. It is said also to have been
found in Dublin and Bantry Bays ;
but this wants con-
firmation. Dr. Turton's specimen from the first of
these localities looks too highly coloured to be British,
and is more probably of foreign extraction. The collec-
tion of Irish shells made bv the late Mr. T. W. Warren,
and now in the museum of the Boyal Dublin Society,
contains a single valve of A. hirundo, which, according
to Mr. Warren's Catalogue, was found by him at Portmarnock.
This specimen has been kindly sent to me
by Dr. Carte, the Superintendent of the museum, for
my inspection. Together with it, and on the same
tablet, is a young shell of a tropical species
of Avicula
(or Meleagrina) , which is not unfrequently met with on
the bottoms of vessels from South America. The pre-
sent species, being in our seas an inhabitant of deep
water and always attached, is not likely to be thrown up
on a sandy shore. I have never heard of a Pinna being
picked up as a similar waif of the ocean. Dr. Carte informs
me that wrecks too frequently occur in Dublin
Bay, which is completely exposed to eastern gales and
situate in very nearly the same parallel of latitude as
Liverpool, to which port
the unfortunate merchant