Pvn H,i I'UitlS

NUCULA. 149
3. N. ni'tida*, G. B. Sowerby.
X. nitida, Sow. Conch. 111. (Nucula) p. 5, f. 20 ; F. & H. ii. p. 218, pi. xlvii.
f. 9.
Body similar to that of N. nucleus ; but the gills are light
brown, smoother outside, and more strongly striated on the
inner surface : foot of a paler colour, and its disk less deeply
serrated at the margin.
Shell acutely triangular, convex towards the beaks, but
compressed in front, moderately solid, remarkably glossy :
sculpture nearly the same as in jV. nucleus but the ; longitudinal
striae are slighter, and the transverse striae are stronger,
especially at the sides, giving the surface a partly cancellated
or notched appearance at the points of intersection ; the lunule
is only marked by the lines of growth, and the dorsal area is
smooth: colour milk-white under the epidermis, which is
yellowish-brown, highly polished and lustrous, without any
trace of the microscopical lines or wrinkles observable in
the foregoing species; the latter is sometimes beautifully
tinted with yellow or purplish -brown longitudinal streaks,
which are arranged in irregular bundles, and resemble the
rays of the setting sun : margins
truncate on the anterior
side, forming an obtuse angle where it joins the ventral range,
rounded in front, and slightly produced or wedge-shaped at
the posterior side : beaks prominent, apparently overhanging
the anterior margin owing to its truncature, and re-
curved : lunule as in the last species, but deeper immediately
below the beaks, and not so much raised, separated
from the
rest of the shell by a blunt ridge in each valve : ligament very
slight: cartilage pear-shaped; cavity larger and projecting
more than in the last : species hinge-line slightly curved :
hinge-plate rather narrow : teeth long, sharp, and recurved,
about twelve on the anterior, and twenty on the posterior
side : inside highly nacreous and iridescent, conspicuously
striated lengthwise, strongly notched on the ventral and
anterior margins, but the crenulations do not extend to the
posterior angle : muscular scars oval, not very
B. 0-45.
Habitat :
distinct. L. 0*4o.
With the last, but neither so generally dif-
fused nor so plentiful. I have taken it at low spring-tides,
* Shining.