. Bulletin of the British Museum (Natural History) Geology Supplement. 206 MKSOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS with short spines, simple or bifurcate : arrangement is in general random, but sometimes in rows, suggesting traces of tabulation. Equatorial zone, corresponding to cingulum, lacking spines : not hollowed. No pattern of sutures visible, no clear indication of sulcus. Apical archaeopyle formed by schism of shell on angular line of breakage. Type species. Doidyx anaphrissa sp. now Lower Cretaceous (Lower Barre- mian) ; England. Remarks. In its asymmetrically biconical shell, spi
. Bulletin of the British Museum (Natural History) Geology Supplement. 206 MKSOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS with short spines, simple or bifurcate : arrangement is in general random, but sometimes in rows, suggesting traces of tabulation. Equatorial zone, corresponding to cingulum, lacking spines : not hollowed. No pattern of sutures visible, no clear indication of sulcus. Apical archaeopyle formed by schism of shell on angular line of breakage. Type species. Doidyx anaphrissa sp. now Lower Cretaceous (Lower Barre- mian) ; England. Remarks. In its asymmetrically biconical shell, spine cover and absence of tabulation, this new genus differs from all described fossil genera. The asymmetry and mode of archaeopyle formation suggests a probable derivation from the genus Pseitdoceratium by reduction of polar horns and loss of the lateral horn. Doidyx differs from Diconodinium, Palaeohystrichophora and Dioxya in its asym- metrical shape : from Diconodinium also in the absence of a sulcus : from Palaeo- hystrichophora also in the lack of an inner body ; and from Dioxya in the clear indication of a cingulum. It differs from the superficially similar genus Aptea in the lack of an enclosing membrane. Doidyx anaphrissa sp. nov. PL 22, fig. 8 ; PI. 23, fig. 6 ; Text-fig. 55 Derivation of name. Greek, anaphrisso, to bristle. Diagnosis. A Doidyx having an asymmetrically biconical shell with short, blunt apical horn and with low bump on antapex. Spines simple, capitate or briefly bifurcate. Portion thrown off in archaeopyle formation exceeding one-third of shell Fig. 55. Doidyx anaphrissa sp. nov. Holotype, showing archaeopyle formation. 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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