History of British animals - University of Guam Marine Laboratory

412 MOLLUSCA. MYTILID^. Modiola.EXTINCT SPECIES.1 . M. amplus.— Depressed, triangular, acutely angled at the base ; longitudinallystriated, excepting over the posterior side ; thin—Sower. Min. Conch.t. vii.—In Oolite.2. M. antiquorum.—Elongated, ovate, rather gibbose, smooth, straight;beaks obtuse, nearly close ; hinge toothed. — Sower. Min. Conch, t. cclxxv.1, 2, 3.—In Crag.3. M. alceformis — Obovate, with an acuminated beak, curved, depressed,smooth, with teeth in the hinge. Sower. Min. Conch, t. cclxxv. f. 4.—InCrap.4. M. pectinatus— Quadrangular, oblong, gibbose, longitudinally striated ;slightly curved beaks ; produced ; front straight.— Sower. Min. Conch, t.cclxxxii.— Upper Oolite.5. M. edentulus.— Elongated, smooth ; disk obscurely keel-shaped ;beaksharp ; posterior side nearly straight ; no tooth in the hinge.—Sower. Min.Conch, t. ccccxxxix. f. 1—In Green Sand.6. M. lanceolatus.— Lanceolate, slightly curved, smooth ; disk keel-formed ;posterior side flat ; beaks acute.—Sower. Min. Conch, t. ccccxxxix. f. 2—InGreen Sand.7. M. subltevis— Oblong, triangular, rather curved ; disk obscurely keelshaped; front straightish ; beaks acute ; lines of growth rather prominent.Sower. Min. Conch, t. ccccxxxix. f. 3—Lower Oolite.8. M. Braardii.— Convex, straight, pear-shaped, elongated; beaks acute,terminal, (within each beak a plate is extended to the opposite edge for thesupport of a tendon, and within that is a flat angular process)—Sower. Min.Conch, t. Dxxxii. f. 2—In Crag.9. M. affinis.— Obliquely oblong, carinated, smooth ; sides parallel, straight ;the posterior arched in the young shell ; hinge without teeth, its anteriormargin reflected—Sower. Min. Conch, t. Dxxxii. f. 1.—In Crag.10. M. crassus. — Shell very thick, ventral edge nearly straight, beak9pointed. Flem. Edin. Phil. Journ. No. XXIV. 246, tab. ix. f. 3. Gregarious.In limestone slate-clay and clay ironstone in the independent coal formation inScotland.Gen. CIV. MODIOLA. — Shell subtransverse, equivalve ;beaks nearly terminal, hinge without teeth, and the ligamentexternal.419. M. vulgaris.— Shell smooth, or slightly wrinkled, compressedand prominent at the extremity of the ligament beaks;tumid.List. Conch, t. Mlvii. f. 5.Mytilus modiolus, Linn. Syst.i. 1 158. Mont.Test. Brit. 165.—On hard ground beyond low water-mark.Length 5 or 6 inches, breadth about one-half less ; rounded at both extremities; cuticle thick, yellowish-brown, sometimes with simple leaf-like filaments.In this last state, it is the Mytilus barbatus of Montagu. In somecases, it is distorted by the byssus, and is then the M. umbilicatus of Pennant-— This species is eagerly sought after, as a bait for cod.