566 PLIOCENE MOLLUSCA. 



Specific Characters. — Shell small, solid, turreted ; whorls 8, slightly convex, 

 the last about three-eighths the total length ; ornamented by strong, prominent,, 

 rounded costa3 which do not quite reach the base, equal in width to the spaces 

 between them ; spire long, slender, gradually tapering to a blunt twisted point ; 

 suture fairly deep ; mouth small, oval, slightly compressed above, expanded below. 



Dimensions. — L. 4 mm. B. 1 mm. 



Distribution. — Not known living. 

 Fossil : St. Erth. 



Bemarl's. — The shell now figured, which is not very rare at St. Erth, was at 

 first thought to be identical with a Miocene species — the Auricula costellata of 

 Grateloup, but this vicAv was objected to by M. Dollfus and was probably a mistake. 

 Grateloup says the mouth of his species was " intiis substiiato,'' and of this the St. 

 Erth specimen, though apparently unworn, shows no trace. As I cannot find 

 anything to which I can with certainty refer it, it may be desirable to give it pro- 

 visionally a distinctive name. It is an interesting form, and the specimen now 

 figured is so beautifully perfect that it deserves notice. It comes from the Wood 

 Collection at the British Museum. 



Turbonilla parvula, sp. nov. Plate XLIX, figs. 22, 23. 



Specific Characters. — Shell short, minute, regularly conical; whorls 6 or 7, 

 nearly flat, the last about one-third the total length, excavated below ; ornamented 

 by about a dozen strong, rounded and oljlique costfB ; spire short, regularly 

 diminishing towards a rounded point; suture distinct, somewhat channelled; 

 mouth small, angulated above. 



Dimensions. — L. 2*5 mm. B. 1 mm. 



Distribution. — Not known living. 

 Fossil : St. Erth. 



Remarks. — The two fossils now represented are from the British Museum,^ 

 where they have been identified with Chemnitzia gracilis and with CJt. pusilla, 

 Phil., respectively. Comparing them, however, with the figures given by 

 that author it seems to me, first that they both belong to the same species, and 

 next, that they differ materially from either of those named in the length of the 

 spire and the coarseness and number of the longitudinal costse. As I cannot find 

 any other form to which they can be satisfactoril}^ referred, I describe them as new, 

 under the name OTven above. 



O" 



Sub-geniis PYRGOSTELIS, Monterosato, 1884. 

 Turbonilla (Pyrgostelis) densecostata (Philippi). Plate XLIX, figs. 24, 25. 



1844 Cheninitzia densecostata, Philippi, Euuin. Moll. Sic, vol. ii, p. 137, pi. xxiv, fig. 9. 

 1848. Chemiiitzin ttensecosfata. S V. Wood, Moil. Ciag Moll, pt. i, p. 82. pi. x, fig. 8. 



