79 MOLLUSCA. 
p- 209; Pecten subrufus, Pennant, p. 100, pl. 60, f. 63; Ostrea 
subrufus and Ostrea opercularis, Donovan, pl. 12; Brown, 
Wernerian Mem., I, p. 513; Maton and Rackett, p. 98. 
Shell slightly oblique, suborbicular, with about twenty 
rounded, divergent ribs; whole surface covered with strong, 
longitudinal, and fine transverse, undulating striae; under valve 
somewhat more convex than the other; auricles nearly equal, 
with very narrow, divergent ribs, and finely striated longitu- 
dinally; colour various, yellow, orange, brown, beautifully 
clouded and variegated with different shades ; inside white, fre- 
quently tinged with pink or lilac, with the ribs and furrows 
strongly marked; margins deeply scalloped; base of the 
auricles terminating externally in an elevated, tooth-like pro- 
cess; above which, on the larger ear, are a few fine, short 
denticles; hinge margin nearly parallel, turned inwards in 
the upper valve, serving as a fulcrum for the hinge line of 
the opposite valve, which is so much shorter than the upper 
valve; umbones sharp pointed. Diameter about two inches 
and a half. 
4, Prcten Istanpicus, pl. XXIV, f. 3. 
Pecten Islandicus, First Ed., pl. 33, f. 3; Chemnitz, VII, p. 
314, pl. 65, f. 615, 616; Lamarck, VI, p. 174; Turton, Biv., 
p- 216; Ostrea cinnabarina, Dillwyn, Cat., p. 256; Brown, 
Ency. Brit., p. 418. 
Shell oblong, narrow above, and widely expanded below; 
with about fifty narrow, slightly elevated ribs, with a groove in 
the centre of each, the intervening furrows provided with a 
narrow, single, less elevated rib; the whole of the ribs covered 
with obtuse, imbricated scales; colour varying from yellowish- 
orange to cinnabar-red, and dark brown. 
Dead shells of this species are common in the Clyde and 
Kyles of Bute, but we only once met with a pair of valves 
united. Large specimens, measuring four inches and a quarter 
in length, were obtained by Henry Gore Booth, Esq., in the 
north end of the West Kyle. 
5. PrEcTEN varius, pl. XXIV, f. 4. 
Pecten varius, First Ed., pl. 33, f.4; Linné, Syst., p. 1146; 
Chemnitz, VII, pl. 66, f. 633, 634; Pennant, IV, p. 101, pl. 
61, f. 64; Montagu, p. 146; Ostrea varia, Maton and Rackett, 
p: 973; Donovan, pl. 1, £13; Brown, Wernerian Mem., II, p. 
513; Ib., Ency. Edin., p. 54, pl. 53, f. 14. 
Shell elongated, with about twenty-eight sharp, narrow echi- 
nated ribs; under valve more convex than the upper one; 
auricles very unequal, diagonally ribbed, and longitudinally 
striated, the larger one in the superior valve is much wrinkled ; 
whole surface covered with nearly equidistant, rough, concave 
spines, which are, however, less numerous towards the um- 
bones; sometimes the spines on the ribs are superceded by 
imbrications, and only slightly echinated towards the sides 
of the valves; beneath the longer ear of the upper valve are 
a few teeth-like processes, at which part there is a hiatus 
betwixt the valves; whole surface variously coloured, some- 
times clouded with dark purplish-brown, burnt umber-brown, 
yellow, or orange; inside coloured like the exterior, but the 
tones more subdued. Length two inches and a quarter; 
breadth two inches. 
Sometimes shells of this species are quite plain, varying in 
colour from deep orange to dark purplish-brown, sometimes 
pure white. 
[ PECTINIDEs. 
This species is not uncommon on most of the coasts of 
Britain and Ireland. 
6. PeEcren nivius, pl. XXII, f. 16. 
Pecten nivius, First Ed. pl. 34, f. 16; Macgillivray, Phil. 
Journ., XIII, p. 166, pl. 3, f. 1; Fleming, p. 384. 
Shell oblong; ears unequal; with forty-two rounded ribs, 
provided with a few scaly spines; the intermediate furrows 
crossed with numerous, transverse strie; external surface of a 
uniform cream-white ; inside snow-white. 
Discovered on the shores of Harris, one of the Hebrides, by 
Professor Macgillivray. 
7. PrcTEN NEBULOSUS, pl. XXII, f. 17. 
Pecten nebulosus, Brown, Report Brit. Association for 1834; 
Ib., Edin. Journ. Nat. Hist., I, p. 9, f. 1. 
Shell nearly circular, the umbones acute; with seven broad, 
flat, unequal, divergent ribs; auricles unequal; external surface 
of both valves covered with very fine, parallel, longitudinal 
strie, and also with very minute, undulating, transyerse striz, 
which are hardly discernible to the naked eye, but feel rough 
to the touch; both valves somewhat inflated towards their 
base, with a series of longitudinal, densely-set ribs, and the 
basal margins finely crenulated two-thirds of the breadth of the 
shell; upper, or convex valve, of a uniform rich reddish-brown, 
irregularly clouded with white; under valve generally ash- 
coloured, and immaculate; inside bluish-white, of a pearlaceous 
lustre, exhibiting iridescent reflections. Length one inch and 
seven-eighths; breadth the same. 
First found at Largs, mouth of the Clyde, by Mr. John 
Blythe, of Glasgow. It has since been found in Loch Fine, 
by Mr. Drew, Writer, Inverary; and I obtained it from Miss 
Helen Carmichael, who found it on the shores of the larger 
Combrie Island, Frith of Clyde. I also met with it, by dredg- 
ing, off Rothesay. 
8. PEcTEN OBSOLETUS, pl. XXIV, f. 6. 
Pecten obsoletus, First Ed., pl. 33, f.6; Pennant, IV, p. 102, 
pl. 61, f. 66; Montagu, p. 149; Donoyan, pl. 1, f. 2; Fleming, 
p- 385; Turton, Biv., p. 213; Forbes, p. 40; Ostea obsoleta, 
Maton and Rackett, p. 100; Brown, Wernerian Mem., II, p. 
514. 
Shell nearly orbicular, rather compressed; with unequal 
auricles, the one large and striated, the other very small; whole 
surface covered with numerous, fine, longitudinal strie, some of 
which are more prominent than the others, and placed at irre- 
gular distances ; variously coloured, sometimes of a uniform 
reddish-brown, or flesh-colour, at others clouded with dark 
purple, or brown; inside smooth, white, or pale lilac, sometimes 
of a brownish cast. 
Not uncommon in the British and Irish seas. 
9. PrcTEen Levis, pl. XXIV, f. 7. 
Pecten levis, First Ed., pl. 33, f.7; Pennant, IV, p. 102; 
Montagu, p. 150, pl. 4, f. 45 Ostvea levis, Maton and Rackett, 
p- 100, pl. 3, f. 5; Brown, Ency. Brit., p. 418. 
Shell suborbicular, valves nearly equal, compressed, thin, sub- 
pellucid ; quite smooth, with the exception of a few concentric 
indications of lines of growth; auricles longitudinally striated, 
and decussated with very fine strie; ears unequal; colour 
various, pink, reddish-yellow, or pale orange; inside glossy, 
bluish-white. Length six-eighths of an inch; breadth not quite 
so much. 
