CYPRIMERIA. 183 



Tf/pe. — From Blackdown ; in the British Museum. 



Distribution. — Upper Greensand (zone of ScKlcenbachia rostrafa) of Blackdown 

 and Haldon. Recorded by Barrois from the Upper Greensand of Lnlworth, and 

 by Jukes-Browne from the Upper Greensand of the Isle of Wight. 



Genus — Cypiumeria, T. A. Conrad, 1864. 



(' Proc. Acad. Nat. Sci. Philad.,' 1864, p. 212, and ' Amer. Journ. Conch.,' vol. ii, I860, p. 102. 

 Stoliczka, ' Palseont. Indica, Cret. Fauna S. India,' 1870, p. 157.) ' 



Sub-genus — Cyclorisma, W. H. Dull, 1903. 



('Proc. U.S. Nat. Mus.,' vol. xxvi, 1903, p. 357. Syn. Cyclothyris, T. A. Conrad in W. C. Kerr's 

 'G-eol. Rep. N. Carolina,' vol. i, Appendix 1 (1875), p. 8. Non Gyclothyris, M'Coy, 1844.) 



Cyprimeiua (Cyclorisma) vectensis (Forbes), 1845. Plate XXVIII, figs. 11 — 18. 



1845. Venus vectensis, E. Forbes. Quart. Journ. Geol. Soc, vol. i, p. 240, pi. ii, 



fig. 4. 

 1850. A. d'Orbigny. Prodr. de Pal., vol. ii, p. 118. 



1854. /. Morris. Cat. Brit. Foss., ed. 2, p. 231. 



1865. — F.J. Pictet and G. Campiche. Foss. Terr. Cret. Ste. 



Croix (Mater. Pal. Suisse, ser. 4), 

 p. 188. 

 1870. F. Stoliczka. Paloeont. Indica, Cret. Fauna S. India, 



vol. iii, p. 160. 

 ? 1883. W. Keeping. Foss., etc. Neoc. Upware and Brickhill, 



p. 125. 



Description. — Shell oval, or nearly orbicular, a little longer than high, regularly 

 convex, slightly or moderately inequilateral. Margin rounded. Umbones small, 

 pointed, somewhat curved forwards. Lunule indistinct, not impressed, limited by a 

 faint line. Pallial sinus angular, directed upwards. Margins of valves smooth. 

 Surface of shell smooth except for small, inconspicuous, concentric ridges, and 

 occasional growth-rings. 



Hinge : In the right valve an anterior and a median cardinal and two posterior 

 laminar teeth (which together represent the posterior cardinal) diverge from 

 under the umbo ; the anterior is directed forwards, the median is nearly vertical, 



1 The following European species are referred by Conrad and by Stoliczka to the genus 

 Cyprimeria: Cycl ina primseva, Zitt., Dosinia cretacea, Zitt., Circe discus (Math.), Circe concentrica, 

 Zitt., and Arcopaaia rotundata, d'Orb. Holzapfel figures Cyprimeria Geinitzi (Mi'ill.) and C. moneta, 

 Holz., from the Aachen Grreensand. 



