228 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



occasionally soleate complexes. Plate i"" possesses an annular complex. Cingu- 

 lum indicated by reduced linear complexes Reflected tabulation of 4', 6", 2-4C, 

 5'", ip, 1"". Archaeopyle apical tetratabular. Well developed sulcal notch on 

 ventral surface and lying to right of mid-ventral line. Outline of central body 

 circular with bilobed antapex. 



Type species. Areoligera senonensis Lejeune-Carpentier 1938ft. Upper Cretace- 

 ous (Senonian) ; Belgium. 



Discussion. Evitt (1961, 1963) has given a full and concise review of the genus. 

 The close relationship to certain species of Cyclonephelium has been noted in preced- 

 ing pages. 



Areoligera coronata (O. Wetzel) 

 PI- 25, fig- 7 



1933. Hystrichosphaera penicillata forma coronata O. Wetzel : 41, pi. 4, fig. 17. 

 1938. Areoligera coronata (O. Wetzel) Lejeune-Carpentier : 168, text-fig. 6. 



Discussion. A. coronata in the Eocene exhibits considerable variation in the 

 structure of the soleate complexes. Proximally these can be fenestrate or non- 

 fenestrate membranes, with the processes arising from the distal margin of the mem- 

 brane. Alternatively, the processes may arise directly from the central body and be 

 united along their length by membranes. Distally the slender processes are erect 

 and can be acuminate or bifid. The number of processes per complex is variable 

 Not infrequently plates 2'" and 4'" have annular and not soleate complexes ; if this 

 is the case, the processes nearest the transverse cingulum are usually shorter. In 

 one individual the processes of adjacent complexes are united distally by trabeculae. 



Only plate 6" never has processes. The apical plates possess four process groups, 

 the smallest of which is that on plate 1'. This is a single taeniate process branched 

 distally. Plates 2' and 3' have tubular annular complexes, diversely branched dis- 

 tally ; these give the impression of having developed from a simple tubular process. 

 Plate 4' has a taeniate process which is branched distally and is intermediate in size 

 between process 1' and processes 2' and 3'. 



Dimensions. Range observed in London Clay : diameter of central body, 

 length 53-66{i, breadth 57-76(0. ; length of processes 10-38(1. Number of specimens 

 measured, 5. 



Occurrence. Eocene, London Clay ; Whitecliff and Sheppey ; Upper Cretace- 

 ous of Germany (O. Wetzel 1933). 



Areoligera cf. coronata (O. Wetzel) 

 PI. 25, fig. 5 ; Text-fig. 63 



Description. Included here are three specimens which differ from A. coronata 

 in having process complexes on all the plates, 6" having a soleate complex, whilst 



