PECTEN. 293 



it, and exhibited specimens from the Clyde, at the Edin- 

 burgh meeting of the British Association. It has since 

 been taken by Mr. Smith, Mr. M 'Andrew, Mr. Jeffreys, 

 Mr. Barlee, and others, in many locaUties among the 

 Hebrides. The following will show its range in depth. 

 Lismore and south of Skye in twenty fathoms ; Armadale 

 in twenty-five fathoms ; Loch Fyne and Loch Ranza in 

 forty fathoms ; Mull, in ninety fathoms. Off both east 

 and west coasts of Zetland it has been taken in eighty, 

 and in one instance at the depth of one hundred fathoms 

 (M'Andrew). The variety Dumasii has been taken in 

 Skye (Jeffreys), and Oban (Barlee). 



It is found on the shores of Scandinavia, and in the 

 Mediterranean. 



P. siMiLis, Laskey. 



Minute, longer than broad, quite smooth, bulging out at one 

 of the sides. 



Plate LII., fig. 6, and (animal) Plate S, fig. 1. 



Peden similis, Laskey, Mem. Werner. Soc. vol. i. p. 387, pi. viii. f. 8. — 

 Fleming Brit. Animals, p. 385. — Macgillivr. Moll. Aberd. 

 p. 227.— Brown, Illust. Conch. G. B. p. 73, pi. 25, f. 5, 6. 



Ostrea tumicla, Turt. Conch. Diction, p. 1 32. 



Peden tumidus, Turt. Dithyra Brit. p. 212, pi. 17, f. 3. — Fleming, Brit. Anim. 

 p. 384.— Brown, Illust. Conch. G. B. p. 73. — Hanl. Recent 

 Shells, vol. i. p. 275.— Loven, Index. Moll. Scand. p. 32. 



This little bivalve may readily be distinguished from the 

 other smooth British Pectens, by its length being at least 

 equal to its breadth. It is small, suborbicular, very thin 

 and fragile, transparent, compressed, and more or less 

 shining ; the valves, though equal to each other in con- 

 vexity, are scarcely of the same breadth, the upper, for the 

 most part, projecting rather beyond the ventral margin of 



