History of British animals - University of Guam Marine Laboratory

390 MOLLUSCA. PERNAD^. Gryph^a.3. G. dilatata— Orbicular, obscurely lobed ; upper valve flat, lower valvehemispherical. — Sower. Min. Conch, t. cxlix. f. 1. var. ib. f. 2 In Oolite,4. G. sinuate-— Suborbicular ; one side cuneiform ; beaks very small, laterallyincurved ; one valve convex, subcarinated ; the other nearly flat, witha sinus above the angle of the cuneiform side ; hinge-pit marginal, long, narrow,and curved—Sower. Min. Conch, t. cccxxxvi Iron Sand.5. G. bullata.— Transversely obovate, irregular, smooth, thin, depressed,beaks small; upper valve concave; lateral lobe obscure, when old Sower.Min. Conch, t. ccclxviii. Middle Ooolite.6. G. vesiculosa. — Subrhomboidal, oblong, deep ; lesser valve concave,small, thin ; larger valve curved, composed of several distant coats.—Sower.Min. Conch, t. ccclxix.— In Green Sand.7» G. columba.—Ovate, rounded, expanded posteriorly, smooth ; beak attenuated,incurved, oblique.— Sower. Min. Conch, t. ccclxxxiii. f. 1, 2. — InGreen Sand.8. G. nana Oblong, ovate, rugged, gibbose, beak oblique, incurved ;uppervalve pointed, thick. — Sower. Min. Conch, t. ccclxxxiii. f. 3.—MiddleOolite.9. G. giganleay—Orbicular, rather smooth ; upper valve thin, concave ;lower valve convex, with a small, sharp, incurved beak ; hinge small.—Sower.Min. Conch, t. cccxci— Under Oolite.10. G. Maccullochii.— Obovate, oblique, gibbose; beak produced, much incurved;posteriorlobe more or less distinct; the front rather angular.—Sower. Min. Conch, t. Dxlvii. f. 1, 2, 3.—In Oolite.11. G. minuta Orbicular, gibbose; beak spiral: lobe obscure—Sower.Min. Conch, t. Dxlvii. f. 4— In Oolite.PERNAD.E.Gen. PERNA.— Shell subequivalve, oblique ;hinge with numeroustransverseparallel teeth, receiving the ligament inthe interstices ;a sinus at the beak for the passage of thebyssus.1 . P. quadrate.— Quadrilateral, one side shorter than the other three ;valves gibbose, unequal, the shorter side very concave, bounded by two obtusecarinse ; beaks prominent Sower. Min. Conch, t. ccccxcii— UnderOolite.Gen. GERVILLIA.— Shell inequivalve, inequilateral, beaksnear the anterior extremity ; hinge long,with numerouspits and lamelliform teeth for the reception of the ligament.1. G.solenoides Transversely much elongated, depressed, smooth; edgesparallel; anterior extremity truncated, open ; teeth of the hinge numerous,variously disposed Sower. Min. Conch, t. bx. f. 1-4—In Green Sand,