. Bulletin of the British Museum (Natural History), Geology. 8o MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS Type species. Hystrichosphaeridium siphoniphorum Cookson & Eisenack 1958. Probably Lower Cretaceous (Albian) ; Australia. Remarks. The presence of three apical processes and the absence of cingular processes is diagnostic of this genus, and makes it easily recognizable. The sulcal processes may be either absent or few. Litosphaeridium siphoniphorum (Cookson & Eisenack) PI. 7, figs. 7, 8 ; Text-figs. 16, 17 1958. Hystrichosphaeyidium siphoniphorum Cookson & Eisenack : 44, pi.
. Bulletin of the British Museum (Natural History), Geology. 8o MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS Type species. Hystrichosphaeridium siphoniphorum Cookson & Eisenack 1958. Probably Lower Cretaceous (Albian) ; Australia. Remarks. The presence of three apical processes and the absence of cingular processes is diagnostic of this genus, and makes it easily recognizable. The sulcal processes may be either absent or few. Litosphaeridium siphoniphorum (Cookson & Eisenack) PI. 7, figs. 7, 8 ; Text-figs. 16, 17 1958. Hystrichosphaeyidium siphoniphorum Cookson & Eisenack : 44, pi. 11, figs. 8-10. 1963. Hystrichokolpoma sp. B., Baltes : 587, pi. 6, figs. 6-8. 1963. Hystrichokolpoma sp. A., Baltes : 587, pi. 6, figs. 1-5. 1964. Hystrichosphaeridium siphoniphorum Cookson & Eisenack ; Cookson & Hughes : 48, pi. 9, fig. 15. Emended diagnosis. Spherical to sub-spherical central body composed of thin endophragm and thick reticulate periphragm. Processes, composed of smooth periphragm, varying considerably in shape and size but commonly cylindrical or sub-conical and always hollow. Distal margin of processes entire or serrate. Hexagonal apical archaeopyle usually present. Number of processes 13, rarely 14 or 15, in specimen possessing an archaeopyle. Inferred tabulation 3', 6", 5'", ip, i"" and 0-2S. HoLOTYPE. National Museum of Victoria, Australia, specimen no. P17468, from Gingin Area, , Seismic shot hole B2 at 230 ft. Horizon—probably Albian. Dimensions. Holotype : overall diameter 76(0., diameter of central body 43ji., length of processes c. ig-24fA. Paratype : overall diameter Ggji., diameter of central body 33ji., length of processes c. x^\l, operculum width 2I[ Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original British Museum (Natural History). London
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