History of British animals - University of Guam Marine Laboratory

Cerithium. MOLLUSCA. CERITHIAM1. 357Trans, vii. 117. t. xi. f. 2.—Murex def. Sower. Min. Conch, t. ccccxi. f. 1—In London Clay.8. T. sexdentatus. — Ovate acuminated, costated, longitudinally striated,transversely carinated whorls convex ; ; aperture elongated, with five or sixteeth within its outer lipMurex sex. Sower. Min. Conch, t. ccccxi. f. 3.—Marine formation, Colwell Bay, Isle of Wight.a. Marine.Cerithium.(Strutheolaria.)aa. Fluviatile.Potamedum.Melanopsis.(Pirena.)CERITHIADiE.Gen. LXXXII. CERITHIUM.—Outer margin of the aperturerounded, with an obsolete canal, in many species,at itsretral junctionwith the body-whorl.— 352. C. costatum.' — Whorls ten, a spiral line at the base ofeach, becoming double on the body-whorl.(Stromhiformis costatus, Da Costa, Brit. Conch. 118. t. viii. f. 14.) Strombuscost. Don. Brit. Shells, t. xciv. Mont. Brit. Shells, 255— Englishcoast, rare.Length about half an inch ; brown ;tapering to a fine point ; transverseribs numerous, rounded, slightly waved; aperture ovate; the outer lip a littleexpanded ; inner lip smooth ; canal very short and patulous.353. C. turbiforme.— Whorls seven, destitute of a thread-likelinespiralat the base of each.Mont. Test. Brit. Sup. 110. t. xxx. f. 7 —Found by Mr Laskey on theshores of Nun's Island, Iona.Length about a quarter of an inch ; breadth two-thirds less ; brown ; aperturewhite ;whoi'ls well-defined by the separating line ; transverse ribs abouteighteen ; base smooth ; aperture suborbicular ; outer lip thickened at themargin, and a little spreading.EXTINCT SPECIES.1. C. pyramidalis.— Pyramidal, with six projecting tuberculated angles;whorls ten or eleven, transversely tricarinated, carina? tuberculated ; six compressedtubercles on the upper part of the last whorl ; outer lip expanded. —(Murex angulatus, Brander, f. 46.) Sower. Min. Conch, t. cxxvii. f. 1London Clay.2. C. geminatum.— Conical, elongated, smooth, with seven or eight longitudinallydisposed pairs of acute tubercles on each whorl ; whorls about twelve,lip even. Sower. Min. Conch, t. cxxvii. f. 2.—London Clay.