History of British animals - University of Guam Marine Laboratory

432 MOLLUSCA. MACTRAD^. Amphidksma.465. A. compressum.— Triangularly ovate, compressed,rounded at both extremities.Concha tenuis, List. An. Ang. 174. Conch, t. cclii. f. 88.— Venus borealis,Penn. Brit. Zool. iv. 96—Tellina plana, Don. Brit. Shells, t. lii.f. 1.—Ligula compressa, Mont. Test. Brit. 96— Listera compressa,Turt. Biv. Brit. 51. t. v. f. 1.—In the mud of estuaries.Length l T 8 5th, breadth 2 T3s th inches; thin, translucent, yellowish-white,finely but irregularly striated by the lines of growth ; beaks very small ;asingle tooth in one valve locking into a bifid tooth in the opposite, adjacentto the ligament.466. A. declive.— Compressed, oval-oblong, angular, truncate.,and open retrally.Mya declivis, Mont. Test. Brit. t. i. f. 2—Anatina declivis, Turt. Biv.Brit. 47— Torbay, Dr Turton.Length 1, breadth 1^ inches ; slightly compressed, white, minutely shagreened,beak nearest the retral extremity anteal ; extremity broad, rounded.This species nearly resembles the A. pubescens, but is distinguished, accordingto Dr Turton, " by the large oval projecting teeth, which extendforwards, and have no lateral attachment."467. A. prcetenue.— Shell slightly compressed, transverselyovate, and rounded at both extremities.Mya prsetenuis,Pult. Dorset. 28. Mont. Test. Brit. 41.—Anatinapraet. Turt. Biv. Brit. 48. t. iv. f. 4—Southern shores of England.Length 1 inch, breadth \\ ; rough, retral extremity longest. It is distinguishedfrom the preceding by its rounded retral extremity.468. A. distortum.— Convex, suborbicular, wrinkled.Mya distorta, Mont. Test. Brit. 42. t. i. f. 1.— Anatina dist. Turt. Biv.Brit. 48. t. iv. f. 5.— In crevices of rocks, rare.Diameter nearly an inch ; variable in form from confined situations inwhich it occurs ; rough, wrinkled by the layers of growth ; distinguishedreadily from the preceding by the rounded projecting support for the ligament.** Hinge, with a lateral tooth on each side, in one of thevalves.469- A. prismaticum.— Transversely oblong, rounded anteally,pointed retrally.Mya prismatica, Laskey, Wern. Mem. i. 377> Mont. Test. Brit. Sup.23. t. xxvi. f. 3.—A. prism. Turt. Biv. Brit. 52. t. v. f. 3— Sandybays.Length half an inch, breadth an inch; thin, transparent, glossy, and iridescent; obsoletely striated concentrically, ventral margin slightly rounded ;a single erect tooth in both valves, with corresponding pits for their reception.A specimen, presented to me by Mr Laskey, by whom the shell wasfirst discovered, is greatly more obtuse at the retral extremity.470. A. album.— Transversely ovate, subtriangular ; roundedat both ends, the beak nearest the retral extremity.4