History of British animals - University of Guam Marine Laboratory

Sphenia. MOLLUSCA. MYAD^. 465581. L. Maris. — Retail extremity slightly produced,withthe dorsal margin nearly straight and subrecurved.Mactra hians, Putt. Dorset, 32 Don. Brit. Shells, t. cxl. Mont. Test.Brit. 101 L. oblonga,Turt. Biv. Brit. 64. t. v. f. 6—In sand, beyondlow-water mark.Length 2\ inches, breadth 5 inches; thick, coarsely striated ; it chieflydiffers from the last in its shortness, great breadth, the straightness of thedorsal and ventral margins, and the subrecurved aspect of the posterior extremity.In the L. vulgaris the syphon-mark has a smooth polished border ;in this species the ismargin a little raised.The following shells, which Dr Turton has included in his genus Monta.cuta, with the following character": Shell oval or oblong, equivalve, inequilateral; mostly closed ; hinge with two teeth in each valve, and a cavity betweenthem; lateral teeth none; ligament internal," appear to be the fry ofthe species of the genera Mya and Lutraria, before they have begun to burrowin the sand or mud.1. substriata Shell oval, with obscure longitudinalribs ; |th of an inch inlength; Ligula substriata, Mont. Test. Brit. Sup. 25—M. substriata, Turt.Biv. Brit. 59 Adhering to Corallines and the spines of Echini.2. bidentata Shell ovaL, smooth, with one of the teeth oblique and spoonshapedMya bidentata, Mont. Test. Brit. 44. t. xxvi. f. 5—M. bid. Turt. Biv.Brit. 60 In cavities in old Oyster Shells.— 3. ferruginosa. Shell oblong, slightly striated transversely, with one of the22. t. xxvi.teeth incurved and spoon-shaped — Mya fer. Mont. Test. Brit. Sup.f. 2 M. fer. Turt. Biv. Brit. CO.—In Sand and Clay.4. oblonga Shell oblong, smooth, with all the teeth erect—M. ob. Turt.Biv. Brit. 61. t. xi. f. 11, 12—In Sand.EXTINCT SPECIES.1. Ij.gibbosa "Retral side widest, recurved, truncated and gaping —Sower.Min. Conch, t. xlii.— Oolite.2. L ? striata Transversely oval, compressed, concentrically striated ; posteriorside smallest, rather pointed, gaping;beaks prominent.—Sower, Min.Conch, t. Dxxxiv. f. 1—Green Sand.3. L ? cariuifera. — Transversely oval, elongated, convex, longitudinallystriated ; posterior side smooth, bounded by an obtuse carina, truncated, itsedge straight Sower. Min. Conch, t. dxxiv—Lower Chalk.4. L ? oblata Compressed, transversely oval, with obtuse extremitiesslightly bent ;beaks prominent—Sower. Min. Conch, t. Dxxxiv. f. 3—LondonClay.Gen. CXLI. SPHENIA.— Transverse, inequivalve, inequilateral,open retrally ; hinge of the rightvalve with anelevated transverselydilated tooth, of the left valve with aconcave tooth, and — small denticle before it.— Turton.582. S. Binghami. Shell wedge-shaped,with the concavetooth oblique and inflected.Turt. Biv. Brit. 36. t. cxi. f. 4, 5. and t. xix. 3.—In f. rocks, Torbay.VOL. G I.g