269 



upper and lower margins, and bluntly angular behind. This 

 simple form is covered with minute puncta, amongst which are 

 sparsely scattered a few pits. Edge view, sub-lanceolate ; end 

 view, acute-ovate. Hingement, as in pi. i., fig. 2. 

 Two specimens ; Blue Fullers-earth Clay, Midford. 



48. CYTHERIDEA VENTROSA. sp. 71. 



PI. iii., figs. 10 a, b, c. 



Obovate, but angular and lipped behind, and rather narrowed 

 anteriorly. Convex and quite smooth. Edge view, sharp-oval ; 

 end view, ovate. Hingement, like that of pi. i., fig. 2. 



One specimen ; Blue Fullers-earth Clay, Midford. 



49. CYTHERIDEA PURA, sp. U. 



PI. iii., figs. 11 a, b, c, d. 



A delicate and simple form, much like a common type of 

 Cythere, having a curved dorsal margin, rounded anterior, angular 

 posterior, and swollen ventral margin, defined at each end by a 

 slight depression. Altogether, sub-oval, smooth, and convex. 

 Hingement, as in pi. i., fig. 2. In some respects allied to Cythere 

 virginea, Jones {Monogr. Cretaceous Entom., Palceontographical 

 Society, 1848, p. 15, pi. i., fig. 2n). If magnified 75 diameters, 

 the surface has the appearance of hammered metal. 



One specimen ; Blue Fullers-earth Clay, Midford. 



50. CYTHERIDEA LIMACIFORMIS,* Sp. 11. 



PI. iii., figs. 12 a, 5, c. 



Ovate-oblong, very convex ; hinge-line distinct ; ventral region 

 swollen ; posterior end somewhat angular and lipped. There are 

 some faint ridges parallel with the ventral margin, not well 

 shown in the figure. Hingement, like that of pi. L, fig. 2. 



One specimen ; Blue Fullers-earth Clay, Midford. 



* Like a slug (resting). 



