234 GASTEROPODA. 



Potamaclis per-acuminata (Charlesworth), Morris, 1856. 



Melania per-acuminata. 



Forbes's ' Isle of Wight,' Mem. Geol. Surv. 1850, pi. iv. fig. 5, p. 152. 



Horizon and Locality. 



Oligocene. — Headon Beds. Hordwell. 



Potamaclis turritissima, Forbes, 18.55. 



Melania tiirritissima. 



Lyell's ' aianual,' 1865, ed. 6, p. 200 (woodcut). 



Forbes's ' Isle of Wight,' Mem. Geol. Surv. 1860, pi. Hi. fig. 14, p. 150. 

 Potamaclis turritissima. 



Land- u. Siissw.-Conch. 187?., pi. xx. figs. 5-5'', p. 312. 

 Horizons and Localities. 



Oligocene. — Bembridge Beds. Hempstead. — Headon Beds, Headon 

 Hordwell. 



Potamaclis Woodi, Edwards (MS.). 



Horizon and Localities. 



Oligocene. — Headon Beds. Headon ; Hordwell. 



Genus PARYPHOSTOMA, Bayan, 1873. 

 fitudes Coll. fie. Mines, 1873, fasc. 2. p. 93. 



Keilostoma, Deshayes, 1848 and 1801. 



Trait<5 fil^m. Conch. 1848, pi. 74. figs. 0, 7, p. 40 ; non aMostoma, Fitzinger, 1833. 

 Desc. Anim. sans Vert. 1801, vol. ii. p. 422. 



Paryphostoma minor, Deshayes, 1801. 



Melania maryinata, var. a. 



Coq. Foss. Paris, 1825, vol. ii. pi. xiv. figs. 3, 4, p. 114, non Laraorck. 



Keilostoma minor. 



Desc. Anim. sans Vert. 1861, vol. ii. p. 425. 



Parijphostoma minus. 

 Ann. Soc. K. Mai. Belgique, 1888, vol. xxiii. p. 243. 



Horizons and Localities. 



Upper Eocene. — Barton Beds. Barton. 



Middle Eocene. — Bracklcsham Beds. Bramshaw. 



Paryphostoma turricula, Bmguiore, 1792. 



Bulimus turricula. 

 Encycl. M.5th. 1792, vol. i. (Vers), p. 324. 



Melania marginnta. 

 Ann. Mus. 1804, vol. 4. p. 4.30; 1800, vol. 8. pi. xii. fig. 4. 

 Coq. Foss. Paris, 1825, vol. ii. pi. xiv. figs. 1, 2, p. 114. 



Keilostoma turricula. 



Desc. Anim. sans Vert. 1861, vol. ii. p. 424. 



Paryphostoma turricula. 



Ann. Soc. R. Mai. Belgique, 1888, vol. xxiii. p. 243. 



Horizon and Locality. 



Middle Eocene. — BracMesham Beds. Brackle.sliam H&y. 



