History of British animals - University of Guam Marine Laboratory

Unio. MOLLUSCA. UNIONISE. 417marked by lines of growth ; hinge strong Sower. Min. Conch, t. clxxxv.—In Crag.8. U. Solandrii— Transversely oblong-ovate, slightly arched, rather compressed,thin ; both extremities obtuse ; beaks small, rugose, hinge slender.— (Mya Pictorum, Brander, Foss. 105.) Sower. Min. Conch, t. Dxvii.—InCrag.9. U. concinnus— Transversely oblong, ovate, depressed, nearly smooth,thick ; posterior side very small ; beaks prominent, recurved—Sower. Min.Conch, t. ccxxiii.— Inferior Oolite.10. U. Urii.— Transversely oblong, dorsal margin nearly straight unequallystriated by growth— the lines of Muscle, Ure, Hist. Ruth. 311.;t. xvi. f. 4.— Mya ovalis, Mart. Derb. t. xxvii. f. 1, 2.—In Slate Clay of theCoal Formation.Gen. CVIII.ALASMODON.—Shell transverse, hinge witha single tooth in the right valve, recurved into a dividedtooth in the left ;no lateral teeth.429. A. margarit'if'erum.— Ventral margin slightly concave ;shell, towards the ligamental margin, compressed.Musculus niger. List. Conch, t. cxlix—Mva margaritifera, Linn. Systi.1112. Mont. Test. Brit. 33—Unio marg. Turt. Biv. Brit. 249-t. xvi. f. 1—In gravel in rapid streams.Length about 2, breadth upwards of 4 inches ; cuticle brownish black ;beaks worn, shell thick ;the lines of growth fine ; inside pearly. Pearls arefrequently met with in this species.CARDITAD.E.Gen. CARDITA.—Shell inequilateral;hinge with two teeth,the shortest beneath the beaks, the other oblique and marginalbeneath the insertion of the cartilage.1. C. striata— Quadrangular, gibbous; the beaks placed at one of the anglesedge.— ; obliquely striated from the beaks to the Sower. Min. Conch,t. lxxxix. f. 1— Liferior Oolite.2. C. abrupta— Triangular gibbous, beaks projecting near one angle ; obliquelystriated ; anterior side longitudinally striated ; five or six transversereflected ridges along the front—Sower. Min. Conch, t lxxxix. f. 2 InferiorOolite.3. C. luberculata— Heart-shaped, longitudinally radiated, radii tuberculated; valves equal, laterally compressed, longitudinally subcarinate, one sidesemilobate, the other nearly flat, beaks much incurved Sower. Min. Conch.t. cxliii. In Green Sand.4. C. lunulata— Rhomboidal, pointed, gibbose, transversely costated ; anteriorpart separated by a projecting serrated keel, lunette deeply excavated ;beaks involute. Sower. Min. Conch, t. cexxxii. f. 1, 2. Inferior Oolite.VOL. I. ])d