MESOZOIC AND CAINOZOIC DINOFL AGELLATE CYSTS 'a 



Deflandrea oebisfeldensis Alberti 

 PL 26, fig. 1 



1959ft. Deflandrea oebisfeldensis Alberti : 95. pi. 8, figs. 10-13. 



Discussion. Two specimens from the London Clay are positively identified as 

 D. oebisfeldensis ; one of them does not possess a capsule. 



Occurrence. Eocene, London Clay ; Enborne and Sheppey. Recorded also 

 from the Palaeocene to the Lower Eocene in Germany and from Stalingrad, Russia 

 (Alberti 19596). 



Deflandrea wardenensis sp. nov. 

 PL 26, fig. 5 



Derivation of name. From Warden Point, Sheppey, Kent. 



Diagnosis. Cavate cysts, sub-circular to ovoidal periphragm, one apical and 

 two short antapical horns. Conical apical horn merging imperceptibly into lateral 

 walls; two antapical horns more positively delimited and straight or slightly diverging 

 Length of antapical horns approximately equal. Thin walled ovoidal capsule, 

 closely appressed to periphragm except at horns. Surface of periphragm has short 

 acuminate or blunt processes, not restricted to sutures of cingulum and sulcus. 

 Archaeopyle common. 



Holotype. B.M.(N.LL) slide ¥.51980(1). London Clay ; Sheppey, Kent, 

 sample 2. 



Dimensions. Holotype : periphragm, length $j\l, breadth 46^ ; capsule, 

 length 36^, breadth 43^. Observed range : periphragm, length 46-64^, breadth 

 43-50^, capsule, length 33-41^, breadth 40-46^. Number of specimens measured, 

 6. 



Description. The epitract is longer than the hypotract. In outline the former 

 is conical with convex lateral sides, the latter is rounded with the antapical horns 

 being sharply delimited. All three horns can be acuminate but are more commonly 

 blunt. The antapical horns are well separated. The equatorial and longitudinal 

 furrows are both wide with the latter broadening posteriorly. Five postcingulars 

 have been discerned ; the rest of the tabulation is too difficult to decipher. 



Occurrence. Eocene, London Clay ; Sheppey, Whitecliff and Enborne. 



Remarks. Species of Deflandrea having processes on the sutures of the cingulum, 

 sulcus and plate boundaries are D. denticulata ; D. echinoidea Cookson & Eisenack 

 1958 (Upper Cretaceous ; Australia) ; and D. spinulosa Alberti 1959 (Oligocene ; 

 Germany). All these have distinctive outlines which readily distinguish them from 

 D. wardenensis. 



