History of British animals - University of Guam Marine Laboratory

384 MOLLUSCA. BIVALVIA. Pecten.375. P. sinuosus.— Distorted with numerous foliated or spinousrays.P. minimus, angustior, List. An. Ang. 18G. Conch, t. clxxii. and clxxxix.— Wallace, Ork. 44—P. Pusio, Penn. Brit. Zool. iv. 101. t. lxi. f. 65.P. distortus, Mont. Test. Brit. 148.—P. sinuosus, Turt. Biv. Brit. 210.—In crevices of sea rocks.Length seldom two inches, and breadth an inch and a half; colour various ;lower valve convex, the left nearly flat, especially towards the extremity ;ribs numerous, unequal, and covered with foliaceous spines along the layersof growth. This sjiecies,when lodging in the crevices of rocks, is apt, likethe Mytili, to become distorted by confinement ;a circumstance which has ledsome naturalists to believe (though they admit the existence of a byssus,)that the shell is attached by its lamellar spines, to the rock ;and that it belongsto the genus Hinnites of De France.376. P. glaber.— Shell with seven obsolete ribs and intermediatelongitudinal striae, nearly smooth.Penn. Brit. Zool. iv. 102. Mont. Test. Brit. Sup. 59. t. xxviii. f. GAnglesea and Firth of Forth, rare.Length and breadth about an inch, mottled with brown and yellow, orplain ; the largest ear reticulated, the other striated ; the valves are ratherflat ; minutely striated concentrically by the layers of growth ; inside with21 slender rays, the middle ones in fours.377. P. tumklus.—" Shell equivalve, inequilateral, quitesmooth, with one of the sides produced.'"Turt. Biv. Brit. 212. t. xvii. f. 3—Taken from the Serpula tubularia, inTorbay." Shell a quarter of an inch in diameter, orbicular ;glossy white, transparent,and without striae, ribs, or marks of any kind ;the sides are not equal,in consequence of one of them being prominent in a rounded manner : earsvery nearly equal."** Ears ofthe shell unequal.""*378. P. varius.— Ribs thirty-two, rounded,with numerousscaly spines.P. subrufus, List. Conch, t. 180.— Osti-ia var. Linn. i.Syst. 114G—Pectenvar. P enn. Brit. Zool. iv. 101. t. lxi. f. G4. Mont. Test. Brit. HG.Turt. Biv. Brit. 214.—On oyster beds.Length upwards of two inches ; white, red, or mottled ; spinous scales concaveon the layers of growth furrows ;finely reticulated.379. P- niveus.— Ribs forty-two, rounded, with few scalyspines.Maegillivray, Edin. Phil. Journ. vol. xiii. 1GG. t. iii. f. 1 — From theouter Hebrides.This species differs from the preceding in the pure whiteness of its colour;the greater number of its ribs, with their few scaly spines, and in the furrowsbeing marked with transverse waved striae, instead of reticulations. Iowe the specimen in my possession to the kind attention of Mr Macgillivrav.