RTRSOA SCUTULA. 635 



v. sem'icoHidiits of Montagu was the equivalent of Jl. Hiriata, Adams, Wood rcveiied 

 in 1872 [op. cif., p. 72) to Woodward's specific name of semicostata, Avliicli I now 

 adopt. Witli this M. Dollfus associated a shell fig-ured hy Philippi in 1836 as 

 li. pnlcliella (Enum. Moll. Sic, vol. i, p. 155, pi. x, fig. 12), but he afterwards 

 considered the latter, as Jeffreys did, a different species. The name of our Crag 

 shell may therefore be definitely fixed as li. semicostata, S. Woodward. 



Rissoa scutula, A. Bell. Plate LI, fig. 40. 



1892. Eissna scutula, A. Bell, Re]). Yorks. Phil. Soc, pp. 63, 67, 75, pi. i, fig. 22. 



Specific Characters. — Shell minute, elongato-conical ; whorls 6 to 7, convex, the 

 last about half the total lengtli ; oi'namented by l)ifid longitudinal ril)s, depressed 

 lengthwise in the centre, which die out at the periphery and are separated by 

 rather wide interspaces; spire regularly diminishing upwards towards a blunt 

 apex; suture well-marked ; mouth ovate; outer lip but slightly rounded, thickened 

 externally; inner lip slight; peristome continuous; umbilical chink distinct but 

 narrow. 



Dimensions. — L. 3 mm. B. 1*5 mm. 



Distribution. — Not known living. 

 Fossil : Selsey. 



Remarks. — This interesting fossil, known only 1)y a unique specimen discovered 

 many years ago by Mr. A. Bell at Selsey, belongs to the York Museum. Differing 

 in sculpture from anything known to him, he described it in 1892 under the above 

 name. It may be easily distinguished ])y the curious bifid character of its longi- 

 tudinal costge. 



Rissoa basi-sulcata, Etheridge and Bell. Plate LI, fig. 1 5. 



1898. Risfioa hasi-sidcata, A. Bell, Trans. Eoy. Cleol. Soc. Cornwall, vol. xii, p. 151, pi. ii, fig. 9. 



Specific Characters. — Shell small, broad, thick, conical, with 6 rounded whorls, 

 a rather deep suture, prominent ribs and very finely striated interspaces; mouth 

 broad and expanded ; outer lip varicose, internally grooved ; pillar straight, 

 expanded at the base with a deep sulcus below the periphery, extending from 

 behind the pillai- round the })ase of the shell. 



Dimensions. — L. 5 mm. B. 3 nun. 



Distribution. — Not recorded living. 

 Fossil : St. Erth. 



Remarks. — This shell, regarded by Messrs. Etheridge and Bell as new, was 

 described and figured by Mr. A. Bell in 1898. It is somewhat larger and stronger 

 than most of tiie St. Erth Rissox ; the costee extend nearl}^ to the base of the 



