. Bulletin of the British Museum (Natural History) Geology Supplement. MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 85 Emended diagnosis. Spherical to sub-spherical fibrous central body bearing small number of fibrous processes. Processes cylindrical, solid, erect, simple or branched and distinctly digitate ; intratabular, one per plate area, number never less than 19 or greater than 20. Archaeopyle apical, haplotabular, and reflected tabulation that of the genus Cordosphaeridium. Holotype. Slide PH. 10. Geologisch-Palaontologisches Institut der Universi- tat Tubingen. Lower Oligocene ; Germany
. Bulletin of the British Museum (Natural History) Geology Supplement. MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 85 Emended diagnosis. Spherical to sub-spherical fibrous central body bearing small number of fibrous processes. Processes cylindrical, solid, erect, simple or branched and distinctly digitate ; intratabular, one per plate area, number never less than 19 or greater than 20. Archaeopyle apical, haplotabular, and reflected tabulation that of the genus Cordosphaeridium. Holotype. Slide PH. 10. Geologisch-Palaontologisches Institut der Universi- tat Tubingen. Lower Oligocene ; Germany. Material (figured). () slide ¥.51746(1). 173 feet above base of London Clay ; Sheppey, Kent. Dimensions. Holotype : diameter of central body jj\l, overall diameter i66(jl, length of processes 46-52(1. Range : diameter of central body 45-90^, (mean 69(1.), overall diameter 115-176^. ¥.51746(1) : diameter of central body 64 by 69^, length of processes 33-37jx. Range of London Clay specimens : diameter of central body 50-71(1, length of processes 20-43(1. Number of specimens measured, 12. Description. The central body is characterized by a thick two-layered wall which is up to 2[x in thickness. The processes are strongly fibrous the fibres radiating outwards from the base of the processes over the surface of the central body, and when branched have a characteristic Y-shape. The single sulcal process is always included within the cingulum series. Remarks. This species was originally described and figured by Eisenack (1938c) as Hystrichosphaera cf. rantosa. Eisenack (1954) proposed a sub-species of Hystri- chosphaeridium inodes to include these forms on the basis of similar wall structure. The processes were described as solid, with fibrous branched endings, and the outer layer of the wall of the central body could be thicker than the inner one. The narrow hollow space in the interior of the processes at their base and passing through to the inner wall layer that Klumpp
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