30
PANDORID^.
usual hyaline protrusile valve; this tube is speckled with
minute sand-like ])oints ; each tube is encircled at its base by
a lew cylindrical filaments, which are somewhat longer than
the tubes, and are occasionally speckled with flake-whito
gills and palps pale brown : foot flexible, white, cloven at the
heel, whence byssal filaments are produced.
Shell irregularly rhomboidal, the left or convex valve somewhat overlapping the other, of a membranous consistency,
opaque and lustreless : scalptLire, numerous rows of fine granulated stria), radiating from the beaks to the outer margins
between each of these stritc are five or six rows of minute
and close-set tubercles or pores, which are connected with tlie
tubular structure of the external layer of the shell ; there are
also occasional lines of growth : colour pale yellowish-white
epidermis light-brown, and having an agglutinating property,
by means of which the surface becomes invested with a coat
of sand and Foraminifera or other organic remains : mar
indented in front, curved obliquely upwards to the posterior
side, which is prolonged into a beak-like form and truncated
at that end, with a double but indistinct ridge in the left
valve, and a corresponding furrow in the right ; dorsal margin
incurved : healcs triangailar, inclining to the anterior side
umbones rather prominent : cartilatje golden-yellow, lying
nearly parallel with the hinge-lino, and contained in a groove
in each valve, the sides of which are thickened : himje-line
obtusely angular: him/e-jjlate long, strengthened by a rib in
the left valve, which fits into a slight furrow in the opposite
valve : ossicle irregularly quadrangular, with the broader end
towards the posterior side, where it is notched or forked ; the
narrower end is truncated and placed immediately under the
beaks : inside highly polished and iridescent ; edges thin, reflected or folded outwards in the right valve : muscidar scars
often double. L. 0-875. B. 1-7.
Var. elonqata.
Shell more slender, and transversely elongated : Osteodesma elonqata, (Gray) Hanley, llec. Sh. p. 25,
pi. 13. f. 27.
J
'^
^)
y^
Habitat : All our coasts, in sand, from 4 to 86 f.,
but nowhere common. The variety has been found in
the Hebrides and Shetland. L. Norveyica has not been
noticed as a British fossil ; but Philippi has recorded it
PANDORID^.
usual hyaline protrusile valve; this tube is speckled with
minute sand-like ])oints ; each tube is encircled at its base by
a lew cylindrical filaments, which are somewhat longer than
the tubes, and are occasionally speckled with flake-whito
gills and palps pale brown : foot flexible, white, cloven at the
heel, whence byssal filaments are produced.
Shell irregularly rhomboidal, the left or convex valve somewhat overlapping the other, of a membranous consistency,
opaque and lustreless : scalptLire, numerous rows of fine granulated stria), radiating from the beaks to the outer margins
between each of these stritc are five or six rows of minute
and close-set tubercles or pores, which are connected with tlie
tubular structure of the external layer of the shell ; there are
also occasional lines of growth : colour pale yellowish-white
epidermis light-brown, and having an agglutinating property,
by means of which the surface becomes invested with a coat
of sand and Foraminifera or other organic remains : mar
indented in front, curved obliquely upwards to the posterior
side, which is prolonged into a beak-like form and truncated
at that end, with a double but indistinct ridge in the left
valve, and a corresponding furrow in the right ; dorsal margin
incurved : healcs triangailar, inclining to the anterior side
umbones rather prominent : cartilatje golden-yellow, lying
nearly parallel with the hinge-lino, and contained in a groove
in each valve, the sides of which are thickened : himje-line
obtusely angular: him/e-jjlate long, strengthened by a rib in
the left valve, which fits into a slight furrow in the opposite
valve : ossicle irregularly quadrangular, with the broader end
towards the posterior side, where it is notched or forked ; the
narrower end is truncated and placed immediately under the
beaks : inside highly polished and iridescent ; edges thin, reflected or folded outwards in the right valve : muscidar scars
often double. L. 0-875. B. 1-7.
Var. elonqata.
Shell more slender, and transversely elongated : Osteodesma elonqata, (Gray) Hanley, llec. Sh. p. 25,
pi. 13. f. 27.
J
'^
^)
y^
Habitat : All our coasts, in sand, from 4 to 86 f.,
but nowhere common. The variety has been found in
the Hebrides and Shetland. L. Norveyica has not been
noticed as a British fossil ; but Philippi has recorded it