History of British animals - University of Guam Marine Laboratory

400 MOLLUSCA. ARCADE. Pectunculus,upon the surface ; anterior margin straight, prominent near the hinge. —•Sower. Min. Conch, t. ccvii. f. 2.— In Green Sand.6. C elongata Elongated, subcylindrical, finely striated ;anteriorlypointed; posterior side very short.—Somffer. Min. Conch, t. ccccxlvii. f. 1Inferior Oolite.7- C. costellala— Transversely oblong, gibbose, longitudinally striated ; anteriorlobe wing-shaped, ribbed ; posterior side rounded, ribbed ; beaks incurved,distant from each other—Sower. Min. Conch, 2.— t. ccccxlvii. f. GreenSand.8. C. minuta— Elongated-ovate, convex, striated, anteriorly submucronated; anterior lobe small, separated by a keel ; beaks nearly close—Sower.Min. Conch, t. ccccxlvii. f. 3— Oolite.9. C. rudis— Transversely oblong, convex, rugged, and longitudinally ribbed; beaks incurved, nearly close together anterior lobe not denned.—;Sower. Min. Conch, t. ccccxlvii. f. 4~-Oolite.Gen. XCIX. PECTUNCULUS.—Shell orbicular, subequilateral;hinge line semicircular, the teeth in the middle obsolete;ligament external.405. P. piloses.— Shell tumid, nearly equilateral, with numerouslongitudinal stria? and transverse lines of growth.P. ingens, List. Conch, t. ccxlvii. f. 82— Arca'pilosa, Linn. Syst.i. 1143.Area Glycymeris, Penn. Brit. Zool. iv. 98, t. lvii. f. 58—A. pilosa,Mont. Test. Brit. 137—Pect. Glycymeris, pilosus, and undatus, Turt.Biv. Brit. 171 Inhabits Weep water.Diameter upwards of 2 inches, covered with a thick, brown, pilose cuticle,underneath which the shell is whitish, with brown interrupted stripes, eithertransverse or longitudinal; beaks tumid, and slightly recurved ; inner marginnotched—This species differs from the P. glycymeris of Lamark in theabsence of the longitudinal ribs, with their intermediate striae.406. P. decussatus.—" Shell orbicular, flat, decussate, withclouded coloured marks."Turt. Biv. Brit. 173, t. xii. f. o—British Channel." Shell an inch in diameter, quite orbicular, flattish, with numerous fineraised decussate lines, which are clothed with a silky brown pile ; colouryellowish-white, with purple and crimson clouded patches, which are oftendisposed in zigzag angles, giving the shell a beautifully marked appearance:inside fglossy white, with frequently a dark red blotch near the centre ; themargin very strongly serrate."— Turton.407. P. nimimarius.—" Shell lenticular, with the beaks permanent,covered with numerous rounded red dots."P. exiguus, List. Conch, t. cexxxix. f. 81.f. 6— Torbay and British Channel.Turt. Biv. Brit. 174. t. xii." Shell about half an inch in diameter, rather convex, very finely decussate,yellowish white, or cream colour, with numerous round red dots, whichvery rarely become confluent about the margin, and form short lines ; beakstumid and prominent, causing the margin on each side of them to appear aprojecting, or, as it were, slightly pecten."— eared like a Turton.