PTTLMONATA. LIMN^IDJE. 281 



Genus ANCYLUS, E. L. Geoffroy, 1767. 

 Traits Coq. Fliiv. Terrest. Paris, 1767, pp. 13, 122. 



Ancylus ? latus, Edwards, 1852. 



Ancylm? latus. 



Moil. Pal. Soc. 1852, pi. xiv. figs. 1.5% 1.5^ p. 110. (F. E. Edwards Coll.) 



Horizon und Locality. 



Olijfrocene.- — Bembrid<ie Beds, lleadon Hill. 



Genus ACROLOXUS, Beck, 1837. 

 Index Molluscorum, 1837, p. 124. 



Velletia, J. E. Grav, 1840. 

 Turton's Man. Shells British Islands, new ed. 1840, p. 250. 



Acroloxus elegans, J. de C. Sowerby, 1826. 



Ancylus elegans. 

 Mineral Conchology, 1826, pi. 533. (Sowerby Coll.) 



Velletia elegans. 

 Mon. Pal. Soc. 1852, pi. xiv. fi<7S. 2a-2", p. 112. (F. E. Edwards Coll.) 



Horizon and Locality, 

 Oligocene. — Headon Beds. Hordwell, 



Genus PLANORBIS (Guettard, 1756), E. L. Geoffroy, 1767. 



Mi5m. Ac. K. Sci. (Paris), 175C, p. 145. 

 Traite Coq. Fluv. Terrest. Paris, 1707, pp. 12, 81. 



Planorbis biangulatus, Edwards, 1852. 



Planorbis biangulatus. 



Mon. Pal. Soc. 1852, pi. xv. figs. 13»-13'', p. 108. (F. E. Edwards Coll.) 



Horizon and Localities, 



Oligocene. — Headon Beds. Hordwell ; Cnlwell Bay. 



Planorbis discus, Edwards, 1852. 



Planorbis discus, 

 Mon. Pal. Soc. 1852, pi. xv. figs. 7»-7", p. 102. (F. E. Edwards Coll.) 

 Land- u. Siissw.-Conch. 1873, pi. xvi. fig. 4, p. 285. 



Horizons and Localities. 



Oligocene.. — Hempstead Beds. Hempstead. — Bembridge Beds. Sconce 

 Point: Bemhridge. — Headon Beds. lleadon Ilill. 



Planorbis elegans, Edwards, 1852. 



Planorbis eleguns. 

 Mon. Pal. Soc. 1852, pi. xv. figs. 12"-12'', p. 107. (F. E. Edwai-ds Coll.) 

 Land- u. Siissw.-Conch. 1873, pi, xv. fig. 14, p. 276. 



Horizon and Locality. 

 Oligocene. — Headon Beds. Headon Hill. 



