THRACIA.
39
Habitat : Cornwall, Devon, and Dorset ; procured
by trawling. The reputed Irish localities are doubtful
this species has been often mistaken for the adult of
T. pajjyracea : the only specimen in Mr. J. D.
Humphreys^s extensive collection of shells from Dublin,
Cork, and Bantry was marked by him '' England.^^ Mr.
Grainger obtained it in a dead state at Belfast, where
it is also found in a post-pliocene deposit, as well as in
the Coralline Crag.
The foreign localities of which I
am assured are Morbihan (Mace and Tasle) ; Provence
(Martin) ; Gibraltar, 8 f. (M'^ Andrew) ; and ^Egean,
70 f. (Forbes) .
Philippi has recorded it as recent at
Naples (on the authority of Scacchi) and fossil at
Palermo.
My largest specimen is 2 J inches long, and 3 J broad.
The young have the same characters as the adult, and
are even more unlike T. papyracea.
The Mya decUvis of Pennant, to which it was at one
time referred, appears to have been the half-grown state
of M. truncata. The present species is the Anatina
myalls of Lamarck, and T. Montagui of Leach.
4. T. convex'a*, W. Wood.
Mya convexa, W. Wood, Gen. Conch, i. p. 92, pi. 18. f. 1. T. conveaa,
R &H. i. p.229, pl.xvi. f. 1,4.
Shell nearly rectangular, extremely gibbous, except towards
the front and posterior side, which are compressed to such an
extent as to give a wedge-like aspect ; it is thinner than T.
puhescens, opaque, and somewhat glossy : sculpture much finer
than that of the last species, and consisting of minute papilla^,
which are equally disposed over the whole surface in transverse
and undulating lines ; the marks of growth are slight, but
numerous : colour pale yellowish-brown : epidermis membranous and thin : margins rounded on the anterior side and in
* Convex.
39
Habitat : Cornwall, Devon, and Dorset ; procured
by trawling. The reputed Irish localities are doubtful
this species has been often mistaken for the adult of
T. pajjyracea : the only specimen in Mr. J. D.
Humphreys^s extensive collection of shells from Dublin,
Cork, and Bantry was marked by him '' England.^^ Mr.
Grainger obtained it in a dead state at Belfast, where
it is also found in a post-pliocene deposit, as well as in
the Coralline Crag.
The foreign localities of which I
am assured are Morbihan (Mace and Tasle) ; Provence
(Martin) ; Gibraltar, 8 f. (M'^ Andrew) ; and ^Egean,
70 f. (Forbes) .
Philippi has recorded it as recent at
Naples (on the authority of Scacchi) and fossil at
Palermo.
My largest specimen is 2 J inches long, and 3 J broad.
The young have the same characters as the adult, and
are even more unlike T. papyracea.
The Mya decUvis of Pennant, to which it was at one
time referred, appears to have been the half-grown state
of M. truncata. The present species is the Anatina
myalls of Lamarck, and T. Montagui of Leach.
4. T. convex'a*, W. Wood.
Mya convexa, W. Wood, Gen. Conch, i. p. 92, pi. 18. f. 1. T. conveaa,
R &H. i. p.229, pl.xvi. f. 1,4.
Shell nearly rectangular, extremely gibbous, except towards
the front and posterior side, which are compressed to such an
extent as to give a wedge-like aspect ; it is thinner than T.
puhescens, opaque, and somewhat glossy : sculpture much finer
than that of the last species, and consisting of minute papilla^,
which are equally disposed over the whole surface in transverse
and undulating lines ; the marks of growth are slight, but
numerous : colour pale yellowish-brown : epidermis membranous and thin : margins rounded on the anterior side and in
* Convex.