. Bulletin of the British Museum (Natural History), Geology. 98 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS Genus TANYOSPHAERIDIUM nov. Derivation of name. Greek, tanyo, long or stretched out ; sphaera, ball— with reference to the elongate nature of the central body exhibited by this genus. Diagnosis. Chorate cysts with elongate central body composed of endophragm and periphragm, the latter also forming the processes. Processes cylindrical, open distally and arranged in more or less regular circular manner around central body. Number of processes variable, usually one or two (occasionally thre
. Bulletin of the British Museum (Natural History), Geology. 98 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS Genus TANYOSPHAERIDIUM nov. Derivation of name. Greek, tanyo, long or stretched out ; sphaera, ball— with reference to the elongate nature of the central body exhibited by this genus. Diagnosis. Chorate cysts with elongate central body composed of endophragm and periphragm, the latter also forming the processes. Processes cylindrical, open distally and arranged in more or less regular circular manner around central body. Number of processes variable, usually one or two (occasionally three) per plate area. Archaeopyle apical. Type species. Tanyosphaeridium variecalamum sp. nov. Upper Cretaceous (Cenomanian) ; England. Remarks. The marked feature of this genus is the elongate nature of the central body. Although the processes are arranged in a distinct circular manner on the surface of the central body, the tabulation is difficult to determine. The number of antapical processes, however, appears to be 3 or 6. Usually there is one or two proces- ses per plate area, but occasionally three may be present. Neither a detached apical region nor a complete specimen has, so far, been observed. Tanyosphaeridium variecalamum sp. nov. PL 6, fig. 7 ; Text-fig. 20 Derivation of name. Latin, varius, different ; calamus, reed—with reference to the rather variable extremities of the Fig. 20. Tanyosphaeridium variecalamum. sp. nov. Holotype, lateral view, showing the circular arrangement of processes around the central body. x c. 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 : BM(NH)
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