ALVANIA OBELISCUS. 613 



tlie Rissoa Lancix of Calcara, was originally discovered by Wood, whose name I. 

 now adopt. 



It belongs to a group of Uissoas rather distinctive of, and common, according 

 to Mr. A. Bell, at St. Erth, in which the upper part of the whorls are covered by 

 fine longitudinal costse and the lower by distinctly-cut spiral ridges. It is specially 

 characterised by the single row of the latter on each whorl near the suture. Our 

 shell is not so tumid as the one figured by Mr. Bell, Ijut he considers it to l)e the 

 same. 



Alvania obeliscus (Etheridge and Bell, MS.). Plate LI, fig. 28. 



1898. Bissoa obsciira, A. Bell, Traus. Roy. Geol. Soc. Cornwall, vol. xii, p. 153. 



Specific Characters. — Shell small, conical ; whorls about 7, nearly flat ; orna- 

 mented by strong longitudinal costge, 15 or 16 on the last whorl, and by well-marked 

 spiral ridges, specially conspicuous near the base ; sutnre distinct but not deep ; 

 spire somewhat elongate, regularly diminishing upwards; mouth ovate, compressed 

 and angulated above, rounded below ; outer lip thin. 



Dimensions. — L. 4 mm. B. 3 mm. 



Distribution. — Not recorded living. 

 Fossil : St. Erth. 



Bemarlis. — The fossil figured nnder the specific and MS. name oheliscns, Etheridge 

 and Bell, was referred by Mr. A. Bell to the B. ohscnra of Philippi,^ ])ut our shell 

 is strongly ridged transversely and of this Philippi's figure shows no trace. He 

 (A, Bell) remarks that it may he a variety of Jl. jmrva, the var. interrapta of which, 

 except for its strong sculpture, it somewhat resembles. On the whole, however, 

 I prefer to regard it as specifically distinct. It is of a St. Erth type, and in some 

 respects not unlike several shells from that place which are here figured. 



Alvania erecta, A. Bell, MS. Plate LI, fig. 29. 



8i)ec.ific Characters. — Shell minute, ovato-conical ; whorls 6, convex, the last 

 rather tumid, much the largest ; ornamented by numerous fine longitudinal costse 

 which die out at the periphery, and by delicate spiral lines which become somewhat 

 stronger below it; suture distinct and slightly channelled, with a spiral line 

 immediately above it; spire short, regularly diminishing in size towards an acute 

 point; mouth rather small, oval; outer lip gently rounded, incurved above, not 

 much expanded ; inner lip somewhat reflected ; peristome continuous. 



Dimensions. — L. 2 mm. B. 1 mm. 



1 See Pbilippi, Euum. Moll. Sic, vol. ii, p. 127, pi. xxiii, fig. 10, 1844. 



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