. Bulletin of the British Museum (Natural History) Geology Supplement. MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 203 Muderongia staurota sp. nov. PL 21, figs. 6, 7 ; PL 23, fig. 4 ; Text-fig. 53 Derivation of name. Greek, staurotos, cruciform. Diagnosis. A Muderongia having an ovoidal to ellipsoidal enclosing body, prolonged into four strong horns. Apical horn strong and tapering, length slightly less than length of shell alone. Lateral horns quite short, less than shell breadth, at first almost parallel sided, but at about one-third length, anterior margin tapering backward to form an angle
. Bulletin of the British Museum (Natural History) Geology Supplement. MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 203 Muderongia staurota sp. nov. PL 21, figs. 6, 7 ; PL 23, fig. 4 ; Text-fig. 53 Derivation of name. Greek, staurotos, cruciform. Diagnosis. A Muderongia having an ovoidal to ellipsoidal enclosing body, prolonged into four strong horns. Apical horn strong and tapering, length slightly less than length of shell alone. Lateral horns quite short, less than shell breadth, at first almost parallel sided, but at about one-third length, anterior margin tapering backward to form an angle with posterior margin. Antapical horn basically conical, with slight out-bulge at one side ; length also less than length of shell alone. Inner body ovoidal to ellipsoidal. Periphragm smooth or finely pitted ; endophragm varying from smooth to densely granular. Shell showing neither trace of tabulation nor of cingulum or sulcus. An apical archaeopyle is formed. Holotype. () slide ¥.51724(3). Speeton Clay, Shell West Heslerton Borehole at 42-50 metres depth, West Heslerton, Yorkshire. Lower Cretaceous (Lower Barremian). Paratype. () slide ¥.51718(3). Same locality and Fig. 53. Muderongia staurota sp. nov. Left, holotype. Right, paratype. The variation in proportions and in degree of granularity of the inner body is shown : the holotype shows incipient formation of an archaeopyle. 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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