62f) PLIOCENE MOLLUSC A. 



to be very abundant ; in Largo Bay Mr. Bell informs me there is a thick shell-bed 

 of Pleistocene age which deserves the attention of collectors. 



I have received from M. Dautzenberg some Danish specimens of B. mevihraiiacea 

 which correspond satisfactorily with the Belfast fossil now figured. 



Var. labiosa (Montagu). Plate LI, fig. 2, 3. 



1803. Helix labiosa, Montagu, Test. Brit., pt. ii, p. 400, pi. xiii, fig. 7. 



1853. Eissoa labiosa, Forbes and Hanlej, Brit. Moll., vol. iii, i>. 109, pi. Ixxvi, tig. 5 ; pi. Ixxvii, 



figs. 1, 2. 



1858. Sissoa labiosa, H. and A. Adams, Gen. Rec. Moll., vol. i, pi. xxxv, fig. 2. 



1867. Bissoa membranacea, var. venusta, Jeffreys, Brit. Concli., vol. iv, p. 31. 



1892. Eissoa membravacea, Locard, Coq. mar. Cotes de France, p. 166, fig. 143. 



1892. Bissoa membranacea, var. venusta, Praeger, Proc. Roy. Irish Acad. [3], vol. ii, p. 260. 



1893. Bissoa membranacea, A. Bell (pt.), Proc. Roy. Irish Acad. [3], vol. ii, p. 630. 

 1901. Zipfora membranacea, var. labiosa, Conch. Soc. List, Jouru. of Conch., vol. x, p. 18. 



1913. Bissoa membranacea, var. labiosa, Dautzenberg et Durouchoux, Feuille des Jeunes Natur., 

 vol. xliv, p. 28, pi. ii, fig. 1. 



Varietal Characters. — Smaller, shorter and more solid than the type with rather 

 stronger ribs. 



Dimensions. — L. G mm. B. 3 mm. 



Distribution. — Recent: British coasts — principally southern. South Wales, 

 West of Scotland, Irish coasts. Norway to Mediterranean. 



Fossil : Estuarine clays, Belfast ; elsewhere in Pleistocene 

 deposits with the type form. 



Remarks. — It seems probable that the specimen of R. lalnosa, originally 

 described by Forbes and Hanley and IL and A. Adams, copied afterwards by 

 Locard, was incorrectly drawn. It shows a tumid shell with very oblique costse, 

 the like of which M. Dautzenberg informs me he has never seen elsewhere during 

 the whole of his experience. As this mistake must have been a source of difficulty 

 to others beside myself, I now give a verified specimen of the recent form received 

 from M. Dautzenberg, for comparison with Forbes and Hanley's shell on the 

 one hand and our Belfast fossil, with which it closely corresponds, on the other. 



Rissoa elata, Philippi. Plate LI, fig. 4. 



1844. Bissoa elata, Fliilippi, Enum. Moll. Sic, vol. ii, p. 124, pi. xxiii, fig. 3. 



1853. Eissoa labiosa, Forbes and Hanley, Brit. Moll., vol. iii, p. Ill, pi. Ixxvii, fig. 3 ; pi. Ixxxi, fig. 3. 



1867. Bissoa membranacea, var. elata, Jeffreys, Brit. Conch., vol. iv, p. 31. 



1873. Bissoa elata, Weinkauff, Cat. europ. Meeresconch., jj. 18, no. 276. 



1874—76. Eissoa elata, Seguenza, Boll. R. Com. Geol. Ital., vol. v, p. 4, no. 356, 1874; vol. vii, 



p. 102, no. 665, 1876. 

 1878. Eissoa membranacea. Reeve, Concli. Icon., vol. xx, pi. viii, fig. i!>7 . 



