72 



MOLLUSCA. 



[Pectinides. 



p. 209; Pecten subrufus, Pennant, p. 100, pi. 60, f. G3; Ostrea 

 subrufus and Ostrea opercularis, Donovan, pi. 12; Brown, 

 Wemorian Mem., II, p. 513 ; Maton and Rackett, p. 98. 



Shell slightly oblique, suborbicular, with about twenty 

 rounded, divergent ribs ; whole surface covered with strong, 

 longitudinal, and line 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. Pecten Islandicus, pi. XXIV, f. 3. 



Pecten Islandicus, First Ed., pi. 33, f. 3; Chemnitz, VII, p. 

 314, pi. 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. Pecten varius, pi. XXIV, f. 4. 



Pecten varius, First Ed., pi. 33, f. 4; Linne, Syst., p. 1146; 

 Chemnitz, VII, pi. 66, f. 633, C34 ; Pennant, IV, p. 101, pi. 

 61, f. 64; Montagu, p. 146; Ostrea varia, Maton and Rackett, 

 p. 97; Donovan, pi. 1, f. 1 ; Brown, Wernerian Mem., II, p. 

 613 ; lb., Ency. Edin., p. 54, pi. 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. 



This species is not uncommon on most of the coasts of 

 Britain and Ireland. 



6. Pecten nivius, pi. XXII, f. 16. 



Pecten nivius, First Ed., pi. 34, f. 16; Macgillivray, Phil. 

 Journ., XIII, p. 166, pi. 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 striae ; external surface of a 

 uniform cream-white ; inside snow-white. 



Discovered on the shores of Harris, one of the Hebrides, by 

 Professor Macgillivray. 



7. Pecten nebulosus, pi. XXII, f. 17. 



Pecten nebulosus, Brown, Report Brit. Association for 1834; 

 lb., 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 

 striae, and also with very minute, undulating, transverse striae, 

 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, oft" Rothesay. 



8. Pecten obsoletus, pi. XXIV, f. 6. 



Pecten obsoletus, First Ed., pi. 33, f. 6; Pennant, IV, p. 102, 

 pi. 61, f. 66; Montagu, p. 149; Donovan, pi. 1, f. 2; Fleming, 

 p. 385; Turton, Biv., p. 213; Forbes, p. 40; Ostrea 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 striae, 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. Pecten ljevis, pi. XXIV, f. 7- 



Pecten Icevis, First Ed., pi. 33, f. 7; Pennant, IV, p. 102; 

 Montagu, p. 150, pi. 4, f. 4 ; Ostrea Ituvis, Maton and Rackett, 

 p. 100, pi. 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 striae ; 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. 



