MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 217 



Holotype. B.M.(N.H.) slide ¥.51975(1). London Clay ; Whitecliff, sample 

 WC 16. 



Dimensions. Holotype : diameter of central body 44 by 59^. Length of 

 processes up to 23^. Observed range : diameter of central body 44-71^. Length 

 of processes up to 23^. Number of specimens measured, 3. 



Description. The processes of A. multispinosum are of approximately equal 

 length in an individual and rarely exceed half the smaller diameter of the central body. 

 They are erect or slightly curved, taeniate, branching from two thirds along their 

 length to the distal extremity. The trabeculae often have short unconnected spines, 

 sometimes arising from bulbous swellings ; the spines can be slender, up to 6jj. in 

 length or short and conical. Occasional wider processes occur. The arrangement of 

 the processes on the central body is variable ; they can lack any regularity or be in 

 soleate or annular complexes. 



Occurrence. Eocene, London Clay ; Whitecliff. 



Remarks. A. multispinosum differs from A. filiferum (= Cannosphaeropsis 

 filifera Cookson & Eisenack) in possessing more numerous, generally very slender 

 processes which can branch from two thirds along their length. Cannosphaeropsis 

 tutulosa Cookson & Eisenack (1960a), from the Upper Cretaceous of Australia, has 

 fewer processes which divide distally and join with neighbouring branches to form a 

 series of relatively wide deep loops apparently lacking spines. 



? Adnatosphaeridium patulutn sp. nov. 

 PL 24, figs. 1, 2 ; Text-fig. 58 



Derivation of name. Latin ; patulus, spread out, broad. 



Diagnosis. Sub-spherical central body with fibrous wall up to i\i thick, composed 

 of endocoel and pericoel. Processes intratabular open, flared, with fibrous walls ; 

 one per plate. Adjacent processes united distally. Archaeopyle haplotabular. 



Holotype. B.M.(N.H.) slide ¥.51977(1). London Clay ; Enborne, sample E 11. 



Fig. 57. Adnatosphaeridium multispinosum sp. nov. Holotype. 

 Archaeopyle shaded, sulcal notch on the left. 



