18G CRETACEOUS LAMELLIBRANCHIA. 



The hinge differs from that of other species of Cyclorisma in that the anterior 

 tooth in the left valve is continued forwards into a ridge at the inner margin of 

 the hinge-plate. 



Lucina ? solidula, Forbes, .appears to be identical with Venus parva, Sowerby; 

 the type is missing, but other specimens which are in the Museum of the Geological 

 Society and were probably identified by Forbes, are undoubtedly examples of 

 V. parva. The type of Lucina? solidula, so far as one can judge from the figure, 

 seems to have been rather shorter than most examples of Venus parva. 



Venus Orbignyana, Forbes, 1 from the Crackers of Atherfield, is stated to be 

 allied to V. parva. The type is missing, but a specimen named V. Orbignyana in 

 the Museum of the Geological Society appears to be a small example of Gyprina 

 Saussuri (p. 131). 



Remarks. — Examples of this species vary somewhat in convexity, in relative 

 height and length, in the prominence and position of the umbones, and in the 

 projection of the lunule at the margin where the valves meet. The types are 

 internal casts from Parham, and they agree, except in being slightly more convex, 

 with casts from East Shalford, where specimens with the shell preserved are also 

 found. The latter do not differ from the perfectly preserved specimens found in 

 the Crackers of Atherfield. 



Type. — From the Sandgate Beds of Parham Park, in the British Museum. 



Distribution. — Lower Greensand : Perna-bed, Crackers, and Bed 45 of Ather- 

 field. Perna-hed of Sandown. Atherfield Beds of Peasmarsh and Shalford. 

 Sandgate Beds of Parham Park. 



Cyprimeria (Ctcloeisma) rotomagensis (d'Orbigny), 1845. Plate XXIX, figs. 4—6. 



1845. Venus rhotomagknsis, A. d'Orbigny. Pal. Franc;. Terr. Cret., vol. iii, p. 



443, pi. ccclxxxv, figs. 1 — 5. 

 1850. rothomagensis, d'Orbigny. Prodr. de Pal., vol. ii, p. 194. 



1865. rotomagensis, F. J. Pictet a i/d G. Campiche. Poss. Terr. Oct. 



Ste. Croix (Mater. Pal. Suisse, 



ser. 4), p. 190. 

 1S70. F. Stolickza. Palseont. Indica, Cret. Fauna S. 



India, vol. iii, p. 161 (7 Caryatis). 



Remarks. — The English examples of this species are internal casts occasionally 

 with small portions of the shell preserved. D'Orbigny 's specimens were obtained 



1 'Quart. Joui n. Grcol. Soc.,' vol. i (1845), p. 240, pi. ii, fig. 5; d'Orbigny, 'Prodr. de Pal.,' 

 vol. ii (1850), p. 118; Morris, 'Cat. Brit. Foss.,' ed. 2 (1854), p. 231; Pietet and Campiche, ' Foss. 

 Terr. Cret. Ste. Croix' ('Muter. Pal. Suisse,' ser. 4, 1865). pp. 184, 188; Stoliczka, 'Palseont. Indica, 

 Cret. Fauna S. India,' vol. iii (1870), p. L60. 



