Pvn H,i I'UitlS

TELLINA. 375
of Leach's genus Arcopagia, which Leach himself has
since denominated Cydippe. It is the Pectunculus de-
pressior of Da Costa, T. rigida of Pulteney, T. subrotunda
of Deshayes, and Cydippe Listeriana of Leach; the
young appears to be the Arcopagia ovata of Brown, and
(in a " depauperated " and dirty state) is certainly the
T. maculata of Turton. Adams's species of the last
name is probably the T. bimaculata of Linne, a very
common West-Indian shell.
B. Shell triangular, inequilateral, produced at the posterior
end to an angular point, concentrically striated (one spe-
cies having the right valve sculptured also by oblique
longitudinal striae); lateral teeth wanting or imperfectly
developed.
3. T. balthica*, Linne.
f. balthica, Linn. Syst. Nat. p. 1120. T. soluhda, F. & II". i. p. 304,
pi.
xx. f. 6.
Body thick, pale yellowish, tinged
brown :
white filaments :
with different shades of
mantle of a firm texture, fringed with fine, but short,
tubes nearly hyaline, varying considerably in
length both collectively and individually ; the excretal one is
curved upwards, and usually longer than the other, being often
exserted to almost twice the length of the shell, plain at its
the alimentary tube has from four to six very minute
orifice ;
dentations at its aperture :
gills two only, one on each side,
rather elongated: palps enormous, triangular, broad at their
bases and pointed at their extremities, smooth without and
distinctly striated within : foot white, very large, muscular, of
moderate length, slightly bent.
Shell more triangular than round, usually convex and
sometimes almost globular, varying in thickness according to
the nature of its :
habitation, opaque, glossy sculpture, fine,
minute, and close-set but irregular concentric striae, diversified
by occasional lines of growth : colour, of all hues and shades
from milk-white or yellow to crimson, often relieved by narrow
zones or concentric belts of a deeper tint, rarely pink in the
Inhabiting the Baltic.