History of British animals - University of Guam Marine Laboratory

388 MOLLUSCA. BIVALVIA. Lima.Gen. XC V. LIMA.— Shell longitudinally oblong, with ears ;beaks remote ;ligament external.385. L. fragilis.— Shell with irregular longitudinal roughribs ; the ears oblique.Pecten frag. Mont. Test. Brit. Sup. 62—L. bullata, Turt. Biv. Brit. 217-t. xvii. r. 4, 5. — On different parts of the coast, rare.Length sometimes exceeding an inch and a half ;breadth an inch ;white ;valves equal, little raised ;one side with the edge straight ; the other arcuated; ribs numerous, unequal, irregularly grouped, most prominent on themiddle of the shell, and rendered rough by the irregular lines of growth ;margin nearly smooth ;beaks prominent. This shell (which may prove avar. of Ostrea glaciulis of Poli, Test. 11. t. xxviii. f. 19, 20.) was observed byMontagu on the coast of Devon, afterwards by Dr Turton, at Bray, in Ireland; and more recently on the coast of Scotland, near Appin, by CaptainCarmichael.—A single valve, communicated by the last observer, is l T 6 „thsof an inch in length.386. L. subauriculata.— Shell finelystriated longitudinally,the ears nearly rectangular.Pecten sub. Mont. Test. Brit. Sup. 63. t. xxix. f. 2—L. sub. Turt. Biv.Brit. 218—On different parts of the coast, from Devon to Zetland,rare.Length fths ; breadth |th of an inch ; pellucid, nearly equilateral ;twoconspicuous mesial opake striae ; margin slightly crenulated.EXTINCT SPECIES.1. L. gibbosa Elongated, gibbose, smooth, longitudinally plicatemiddle ;ears undefined.— Sower. Min. Conch, t. clii.— Under Oolite.in the2. L. rudis.— Obovate, oblique, with seven longitudinal costae ; anteriorear open with thickened lobes Sower. Min. Conch, t. ccxiv. f. 1.—MiddleOolite.3. L. antiquata Elliptical, depressed, coarsely striated ; anterior eardeeply wrinkled, open Sower. Min. Conch, t. ccxiv. f. 2.— In Lias.4. L. proboscidea Broad, ovate, convex, with twelve ribs, each furnishedwith several large tubular processes ; ears small— Sower. Min. Conch,t. cclxiv.— Inferior Oolite.Gen. PLAGIOSTOMA.— " An oblique eared bivalve ;hingedestitute of teeth or internal pit;line of the hinge straightin one valve, in the other deeply cut by an 1'angular sinus.— (Sowerby.)1. Y.giganteum Smooth, depressed, deltoid, with the posterior side roundedin to the front ; ears small, anterior one longest, placed in a lai-ge broadand straight furrow ; beaks pointed surface ; obscurely marked with diverging— striae. Sower. Min. Conch, t. lxvii—In Lias.2. P. spinosum Obovate, longitudinally furrowed ; sides nearly equal,