NE.ERA.
49
valve, and a slight lateral on the posterior side of the right
valve : inside glossy and nacreous ; posterior side separated by
a sharp rib : scars indistinct. L.0-3. B.0-4.
Habitat : Loch Fyne (M^Andrew and Barlee) ; Skye
and Shetland (Barlee) ; in 40-75 f., on a muddy
ground. Fossil in the Belgian tertiaries (Nyst). Its
known distribution elsewhere in a recent state is as
follows : —Bohuslan (Loven) ; Christiania, 40-100 f.
(Asbjornsen) ; Bergen, 40-50 f. (Danielssen) ; Finmark (Sars and Lilljeborg) ; dead valves in the ^Egean,
75-105 f. (Forbes)
It is the N. vitrea of Loven.
2. N. costella'ta*, Deshayes.
Corbula cosfeUata, Desh. Exp. Scient. Mor. (Geologie) p. 86, t. vii. f. 1-3.
N. costellata, F. & H. i. p. 199, pi. vii. f. 8, 9, and (animal) pi. G. f. 8, 9.
Body gelatinous, clear white : mantle so transparent as to
allow the pink gills and dark brown liver to be seen through
it : tubes cylindrical, sometimes yellow with reddish or orange
markings, and tinged with brown at their extremities; excretal tube much the smaller of the two ; tentacular cirri white
and plain, extending beyond the tubes ; orifices fringed : foot
narrow.
Shell more slender than iV^. ahhreviata, more inequivalve,
much less ventricose and even somewhat compressed, equally
fragile, semitransparent, glossy and iridescent : sculpture,
20-30 longitudinally radiating ribs, which are shghter and
more like striae on the anterior side and in front, but stronger
and more distant towards the posterior side, especially the last
two or three ; these ribs vary in size and fineness ; the prolonged part on the posterior side is also marked with two or
three slight ribs, which are parallel with the dorsal line and
extend to the rostral point : colour and epidermis as in the
species last described : margins also similar, except behind,
where the anterior dorsal margin is raised and appears highshouldered, and the posterior dorsal margin is inflected and
* Fine-ribbed,
VOL. III.
D
49
valve, and a slight lateral on the posterior side of the right
valve : inside glossy and nacreous ; posterior side separated by
a sharp rib : scars indistinct. L.0-3. B.0-4.
Habitat : Loch Fyne (M^Andrew and Barlee) ; Skye
and Shetland (Barlee) ; in 40-75 f., on a muddy
ground. Fossil in the Belgian tertiaries (Nyst). Its
known distribution elsewhere in a recent state is as
follows : —Bohuslan (Loven) ; Christiania, 40-100 f.
(Asbjornsen) ; Bergen, 40-50 f. (Danielssen) ; Finmark (Sars and Lilljeborg) ; dead valves in the ^Egean,
75-105 f. (Forbes)
It is the N. vitrea of Loven.
2. N. costella'ta*, Deshayes.
Corbula cosfeUata, Desh. Exp. Scient. Mor. (Geologie) p. 86, t. vii. f. 1-3.
N. costellata, F. & H. i. p. 199, pi. vii. f. 8, 9, and (animal) pi. G. f. 8, 9.
Body gelatinous, clear white : mantle so transparent as to
allow the pink gills and dark brown liver to be seen through
it : tubes cylindrical, sometimes yellow with reddish or orange
markings, and tinged with brown at their extremities; excretal tube much the smaller of the two ; tentacular cirri white
and plain, extending beyond the tubes ; orifices fringed : foot
narrow.
Shell more slender than iV^. ahhreviata, more inequivalve,
much less ventricose and even somewhat compressed, equally
fragile, semitransparent, glossy and iridescent : sculpture,
20-30 longitudinally radiating ribs, which are shghter and
more like striae on the anterior side and in front, but stronger
and more distant towards the posterior side, especially the last
two or three ; these ribs vary in size and fineness ; the prolonged part on the posterior side is also marked with two or
three slight ribs, which are parallel with the dorsal line and
extend to the rostral point : colour and epidermis as in the
species last described : margins also similar, except behind,
where the anterior dorsal margin is raised and appears highshouldered, and the posterior dorsal margin is inflected and
* Fine-ribbed,
VOL. III.
D