354 DR. GWYN JEFFREYS ON THE MO LLUSCA OF THE [May 20, 



fewer, stronger, and curved ribs. But the specific name must be 

 changed, because it was preengaged by Koch and Weichmaun for a 

 Miocene shell. 



C. Turbonilla or Ohemnitzia. Striated lengthwise or reticulated, 

 and usually toothless. 



D'Orbio-ny, in his work on the Mollusca of the Canary Isles, 

 proposed Chemnilzia 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. 



Turlo indistinctiis, Mont. Test. Br. Snppl. p. 129. 



O. indistincta, B. C. iv. p. 149 ; v. p. 213, pi. Ixxv. f. 1. 



'Porcupine' Exp. 1869: St. 18. 1870: Atl. Vigo B. (rar. 

 brevior), Tangier B. 



Distribution. Bergen southwards to the Mediterranean and 

 Adriatic, Madeira, and Canaries ; 4-60 fms. 



Fossil. Miocene: Vienna Basin {Homes). Pliocene: Coralline 

 Crao' and Italy. Post-tertiary : Norway, West of Scotland, Belfast, 

 and^Selsea ; d-.50 ft. 



In addition to the synonyms given in ' British Conchology ' are 

 Chemnilzia areolata of Rayneval, Truncatella juHcB of de Folin, and 

 0. {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 sigmoideaS Monterosato MS. (Plate XXVI. 

 fig. 9.) 



Shell 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 tw-enty 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 and polished : colour white : spire gradually tapering 

 to a blunt point : w/iorls 8, somewhat compressed ; the last occupies 

 nearly two fifths of the shell : suture slight and shallow, rather ob- 

 lique": 7tioulh 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 n small and narrow 

 chink: tooth or columellar fold none observable. L. O'lo. B. 0'05. 

 1 From the ribs resembling Hie Greek letter siffnia. 



