32 PLIOCENE MOLLUSCA. 



Genus PLANORBIS, Guettard, 1756. 



Planorbis corneus (Linne). 



1767. Helix cornea, Liune, Syst. Nat., ed. xii, p. 1243, uo. 671. 

 1848. Planorhis corneus, S. V. Wood, Mon. Crag Moll., pt. i, p. 10, tab. 1, fig. 12. 

 1853. Planorbis corneus, Forbes and Hanley, Brit. Moll., vol. iv, p. 147, pi. cxxvi, figs. 4, 5. 

 1862. Planorbis corneus, Jeffreys, Brit. Concli., vol. i, p. 93, pi. vi, fig. 3. 

 1890. Planorbis corneus, C. Eeid, Plioc. Dep. Brit., p. 229. 



1897-1901. Planorhis corneus, Keimard and B. B. Woodward, Essex Nat., vol. x, p. 108, 1897 ; Proc. 

 Malac. Soc, vol. iii, p. 196, 1899 ; Proc. Geol. Assoc, vol. xvii, p. 260, 1901. 



Specific Cliaracters. — See Mon. Crag MolJ., pt. i, p. 10. 



Dimensions. — Diam. 9 mm. H. 4"5 mm. 



Distribid'ton. — Recent : local in many parts of England ; confined to a small 

 area in Ireland; on the Euro-Asiatic continent from Siberia to Corsica (Jeffreys) ; 

 Algeria, Morocco. 



FossU : Icenian Crag : — Noncich zone : Sontlnvold, Bulchamp. 

 Weybourne zone : East Runton, North Walsham boring. Pleistocene of England : 

 Barnwell gravels, Holderness and other localities. Holocene : Great Britain. 



Lower Pleistocene : Mosbach. Pleistocene : Denmark. Newer Holocene : 

 Denmark and Sweden (Nordmann). 



BemarJcs. — This species was known to Wood only from Bulchamp. Messrs. 

 Kennard and B. B. Woodward report a single and immature specimen from 

 Southwold, now in the British Museum (Natural History). They also give it from 

 the Holocene and Pleistocene deposits of a number of localities in the south of 

 England. The shell Mr. C. Reid reports from the Weybourne Crag and the West 

 Runton Freshwater bed as P. corneus was regarded by Prof. Sandberger as a 

 different species which he described as P. chithratns. 



Planorbis spirorbis, Miiller. 



1774. Planorbis spirorbis, Miiller, Verm. terr. fliiv. Hist., jit. ii, p. 161, no. 347. 

 1848. Planorbis spirorbis, S. V. Wood, Mon. Crag Moll., pt. i, p. 9, tab. 1, fig. 11. 

 1863. Planorbis spirorbis, Forbes and Hanley, Brit. Moll., vol. iv, p. 159, pi. cxxvii, figs. 9, 10 

 1862. Planorbis spirorbis, Jeffreys, Brit. Couch., vol. i, p. 87, pi. v, fig. 6. 

 1890. Planorbis spirorbis, C. Reid, Plioc. Dep. Brit., p. 229. 



1897-1901. Planorbis spirorbis, Kennard and B. B. Woodward, Essex Nat., vol. x, pp. 93 et seq. 

 1897; Proc. Malac. Soc, vol. iii, p. 197, 1899; Proc Geol. Assoc, vol. xvii, pp. 217 et seq., 1901. 



Specific Characters. — See Mon. Crag Moll., pt. i, p, 9. 

 Dimensions. — Diam. 6 mm. H. 1 mm. 



