CLEMENTIA. 189 



of the postez'O-dorsal margin. In the type specimen that slope is small, so that 

 the outline of the shell is distinctly oval. The position of the umbones also varies, 

 so that some specimens are more inefjuilateral than others. 



Specimens found in the Gault of Black Ven ai'e usually somewhat crushed and 

 often larger than Blackdown examples ; some are more elongate and agree closely 

 with Vemifs sublasvis, Sowerby (see below). 



Ti/jje. — From Blackdown ; in the British Museum. 



Distrihntion. — Upi)er Greensand (zone of ScJihMuhuchia rontratti) of Blackdown 

 and (?) Devizes. Gault of Black Ven. 



Cyprimeria (Cyclouisma) subl^vis (Soioerhi/), 183G. Plate XXIX, fig. 14. 



18.36. Venus? subl^vis, J. de C. Sowerby. Traus. Geol. Soc, ser. 2, vol. iv, pp. 



242, 342, pi. xvii, fig. 5. 

 1850. Venus subl.bvis, A. d'Orhiyny. Prodr. de Pal., vol. ii, p. 159. 

 1854. — — /. Morris. Cat. Brit. Foss., ed. 2, p. 2.31. 



1870. — — F. Sloliczka. Palseont. Indica, Cret. Faima S. India, 



vol. iii, p. 161. 



BemarJcs. — The only specimen which I have seen is the type. It differs from 

 G. {Gydovisma) faba only in being more elongate, and seems to be merely an 

 individual variation. Venus immersa, Sowerby,^ also known by the type only 

 (Plate XXIX, fig. 15), does not appear to differ from V. suhlaimfi. The types of 

 both are in the Bristol Museum and come from the Upper Greensand of Blackdown. 



4 



Genus — Clementia, ./. E. Gray, 18-40. 

 (' Synopsis Brit. Mus.,' p. 149.) 



Sub-genus — Flaventi.x, A. J. Jnkes-Browne, 1908. 

 (' Proc. Malacol. Soc.,' vol. viii, p. 167.) 



Clementia (Flaventia) Ricokde^vna (d'Orbu/ny), 1845. Plate XXIX, figs. 16 — 18. 



1845. Venus Eicobdeana, A. d'Orbigvy. Pal. Franv. Terr. Crot., vol. iii, p. 431, 



pi. ccclxxxii, figs. 1, 2. 



1 Sowerby, 'Trans. Geol. Soc.,' ser. 2, vol. iv (1836), pp. 242, 342, pi. xvii. fig. 6; d'Orbigny, 

 'Prodr. de Pal,' vol. ii (1850), p. 159; Morris, 'Cat. Brit. Foss.,' ed. 2 (1854), p. 231 ; Stoliczka, 

 ' Palajont. Indica, Cret. Fauna S. India,' vol. iii (1870), p. 161. Nou Venus immersa, Midler, ' Petref . 

 der Aacbeu. Kreidef.,' Suj.pleuient (1859), p. 13; Eeuss, ' Die Verstein. der bohm. Kreideforniat.,' 

 pt. 2 (1846), p. 20, pi. xli, fig. 11 ; Kner, 'Denlischr. d. k. Akad. Wissenscb. Wieu, Matli.-Nut. CI.,' 

 vol. iii (1852), p. 311. \<l. xvi. tig. 20. 



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