from the " Cambridge Greensand.^^ 337 



in the enlargement of the pits and of the marginal elevations ; 

 also the central area of tlie valve-surface is more depressed. 

 The anterior border is flange-like, and within this runs a 

 fenestrated ridge. From the invariably large size of the 

 specimens it is just possible that we have here a senile form 

 of G. gaultina ; but since the specimens are so exceptionally 

 rare and the carapace extraordinarily developed, it seems 

 advisable to regard it as distinct, although indicating its 

 relationship with C. gaultina. 



One valve was found in the washings from Swaffham. 



Cy there subtuberculata, sp. n. (Figs. 3 a, b.) 



One of the valves from the Cambridge Greensand of 

 Swaffham, perhaps somewhat allied to the foregoing species, 

 C. gauhina^ is rather more elongate than that species and 



Fi^. 3. 



a. 



~b. 



Cythere suhtuherculata, sp. n. a, left valve ; b, edge of valve. X 40. 



differs materially in the ornamentation by having the poly- 

 gonal reticulation of the surface emphasized by extra shell- 

 growth, tubercular processes being disposed along the dorsal 

 border and towards the posterior extremity of the valve. 



Cythere Koninckiana, Bosquet. (Figs. 4 a, b.) 



Cythere Konmckicma, Bosquet, 1854, Mt%i. Comm. geol. Neerlande, 

 vol. ii. p. 110, jjI. ix. tig. 7 ; Chapman and Sherborn, 1893, Geol. Mag! 

 vol. X. p. 346, pi. xiv. fig. 4 (nou fig. 2). 



Messrs. Jones and Hinde refer some specimens in my 

 collection of Ostracoda from the Gault of Folkestone to this 

 species (Suppl Mon. pp. 52 and 61). None of them are 

 quite comparable with Bosquet's figured specimens, but their 

 relationship is sufficiently evident to warrant their association 

 with this species. 



The figures of Cythere Koninckiana and C. Uneatopunctata 



