Pvn H,i I'UitlS

MYTILUS. Ill
spinning strong tendinous threads, by which she moors
her shell to rocks and timbers." Pearls too are produced
by them in considerable quantities, although of
an irregular shape and indifferent lustre. Formerly
they were applied medicinally as an absorbent. Great
numbers are still collected at the mouth of the River
Conway in North Wales, the fish being boiled and trodden
out by the naked feet of women. What is done with
these " seed-pearls " is a mystery. I have been told
that the Jews purchase them for the Birmingham mar-
ket; and a correspondent in Loudon's Magazine of
Natural History for 1830 mentions a surmise that they
are exported to India to be dissolved in the sherbet of
the nabobs !
This species in a recent and fossil state has received
twenty-eight different names. Its variability
tensive with its diffusion.
2. M. modi'olus *j Linne.
is coex-
M. modiolus, Linn. Syst. Nat. p. 1158. Modiola modiolus, F. & H. ii.
p. 182, pi.
xliv. f. 1,2.
Body dark orange, speckled with white and often tinted
with brown: mantle having both margins plain throughout,
and whitish at
but finely ciliated : foot red on the upper part,
the base, where it is very thick and strongly wrinkled.
Shell oblong, bluntly rounded, nearly square at the smaller
end and expanding outwards to a semicircular edge in front,
convex, and gibbous towards the beaks, solid and glossy :
sculpture, fine concentric lines of increase : colour purplishyellow
: epidermis thick, dark brown or dusky, almost black
in the adult, minutely striate lengthwise, foliated in the
young and produced into long thorn-like filaments, which are
plain at their edges and arranged in concentric rows on the
posterior side and in front :
'margins thick, straight or but
slightly incurved on the ventral side, obtusely
rounded be-
hind and semicircular in front : beaks blunt, divergent and in-
* The box of a pump.