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Show 354 DR. GWYN JEFFREYS ON THE MOLLUSCA OF THE [May 20, fewer, stronger, and curved ribs. But the specific name must be changed, because it was preengaged by Koch and Weichmann for a Miocene shell. C. Turbonilla or Chemnitzia. Striated lengthwise or reticulated, and usually toothless. D'Orbigny, in his work on the Mollusca of the Canary Isles, proposed Chemnitzia as a subgenus of Melania, and said nothing about the heterostrophe apex or any other character which could distinguish it from Eulima, except that it was " fortement costulee." 28. ODOSTOMIA INDISTINCTA, Montagu. Turbo indistinctus, Mont. Test. Br. Suppl. p. 129. O. indistincta, B. C. iv. p. 149 ; v. p. 213, pi. lxxv. f. 1. 'Porcupine' Exp. 1869: St. 18. 1870: Atl. Vigo B. (var. brevior), Tangier B. Distribution. Bergen southwards to the Mediterranean and Adriatic, Madeira, and Canaries ; 4-60 fms. Fossil. Miocene : Vienna Basin (Hornes). Pliocene : Coralline Crag and Italy. Post-tertiary : Norway, West of Scotland, Belfast, and Selsea ; 0-50 ft. In addition to the synonyms given in ' British Conchology' are Chemnitzia areolata of Rayneval, Truncatella julia of de Folin, and O. (Pyrgulina) nanodea of Monterosato. The late General Stefanis obligingly gave me a specimen from the Gulf of Naples, which has the peculiar shape and the delicate flexuous sculpture of the species, as well as a conspicuous tooth in the middle of the pillar. Professor Stossich showed me a similar specimen from the Adriatic. It is quite impossible, even with the aid of a lively imagination, to distinguish Turbonilla or Chemnitzia from Odostomia by any fixed character. 29. ODOSTOMIA SIGMOIDEA \ Monterosato MS. (Plate XXVI. fig. 9.) S H E L L cylindrical, rather thin, semitransparent, and glossy: sculpture, numerous but not close-set longitudinal ribs, of which there are about 25 on the last whorl and twenty on the next; these are oblique at first and afterwards become flexuous ; their interstices are nearly equal in breadth to the ribs, and are throughout finely and closely striated across or spirally ; the base is marked by spiral striae only, as the ribs do not extend below the periphery ; apex quite smooth aud polished : colour white: spire gradually tapering to a blunt point: whorls 8, somewhat compressed ; the last occupies nearly two fifths of the shell : suture slight and shallow, rather oblique : mouth oval, acute-angled above and rounded below ; length equal to one fifth of that of the spire : outer lip flexuous : inner lip narrow, reflected on the pillar, behind which is a small and narrow chink: tooth or columellar fold none observable. L. 0*15. B. 005. 1 From tbe ribs resembling the Greek letter sigma. |