no CRETACEOUS LAMELLIBRANCHIA. 



Ti/pes. — I have not seen the types ; they were obtained from the Hythe Beds, 

 near Hythe. The type of M. spafhnlatus, Seeley, from the Barnwell Gravel 

 (doi'ived from the Chalk), is in the Woodwardian Museum, Cambridge. 



Distribution. — Hythe Beds of Hythe and Lympne. Lower Greensand of 

 Faringdon and Seend. Upper Greensand of Chilfrome (Dorset), and near 

 "Weymouth. Greensand of Haldon. Chloritic Marl of Maiden Bradley. Ceno- 

 nianian (Meyer's Bed 12) of Uunscombe and Kempstone Rocks (Sidmouth). Chalk 

 Marl of Chardstock. Basement Bed of Chalk Marl of Cerne Abbas. Cenomanian 

 Sands of Wilmington. LoAver Chalk of Burwell and Stoke Ferry. Chalk Rock of 

 Winchester, Cuckhamsley, Tjuton cutting, and Underwood Hall (Dullingham). 

 Upper Chalk of Northfleet. Flint gravel (derived from Upper Chalk) near 

 Ventnor. Zone of Bel. qvadrata of Winchester and Salisbury. Zone of Bel. 

 vinrroiiata of Salisbury and Norwich. 



Genus — Drbissensia, P. van Beneden, 1835. 

 ('Ann. Sci. Nat.,' ser. 2, vol. iii, ji. 193, pi. viii. Emend. P. Fisctier, 'Man. cle Concli.,' 1886, p. 972.) 



Dreissensia lanceolata {Sowerbij), 1823. Plate XVIII, figs. 13 — 15; Plate XIX, 



figs. 1—11. 



1823. Mytiltjs edentulus, /. de C. Sowerbij. Min. Conch., vol. v, p. 55, pi. 



ccccxxxix, fig. 1. 

 1823. — LANCEOLATus, Sowerby. Ibid., fig. 2. 



1836. — TRiDENS, J. de C. Sowerby. Trans. Geol. Soc, ser. 2, vol. iv, 



p. 342, pi. xvii, fig. 14. 

 1836. — PRiELONGUs, Sowerby. Ibid., p. 342, pi. xvii, fig. 15. 



1844. — LANCEOLATUS, A. d'Ovbigny. Pal. Fran9. Terr. Cret., vol. iii, 



p. 270, pi. cccxxxviii, figs. 5, 6. 



1844. — FALCATUS, d'Orbicjny. Ibid., p. 280, pi. cccxli, figs. 11 — 13. 



1845. — LANCEOLATUS, var. EDENTULUS, E. Forbes. Quart. Journ. Geol. 



Soc, vol. i, p. 248. 

 ? 1846. — — A. E. Eenss. Die Verstein. der bolim. Kreide- 



format., j^t. 2, p. 15, pi. xxxvii, fig. 5. 

 1848. — — H. G. Bronn. Index Palaeont., vol. i, p. 773. 



1850. MiTYLUs ABRUPTUS, A. d'Orblgmj. Prodr. de Pal., vol. ii, p. 107. 

 1850. — SUBFALCATUS, d'Orbiguy. Ibid., p. 166. 



1850. — LANCEOLATUS, d'0rbi(j7iy. Ibid., p. 166. 



1854. Mytilus EDENTULUS, J. Morvis. Cat. Brit. Foss., ed. 2, p. 215. 

 1854. — LANCEOLATUS, Morris. Ibid., p. 215. 



1854, — PR^LONGus, Morris, Ibid., p. 215, 



