. Bulletin of the British Museum (Natural History), Geology. I go MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS Remarks. W. teniiavirgula var. crassoramosa does not merit raising to specific level, on account of the frequent occurrence of forms transitional to W. tenuovirgula. The extreme development of the secae (more correctly termed bars at this stage of development) however is very distinctive. Wetzeliella (Wetzeliella) homomorpha Deflandre & Cookson 1948. Hystrichosphaeridium geometvicuni Pastiels (pars) : 41, pi. 4, figs. 3, 5, 6, 7, 9, 10. 1955- Wetzeliella homomorpha Deflandre &
. Bulletin of the British Museum (Natural History), Geology. I go MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS Remarks. W. teniiavirgula var. crassoramosa does not merit raising to specific level, on account of the frequent occurrence of forms transitional to W. tenuovirgula. The extreme development of the secae (more correctly termed bars at this stage of development) however is very distinctive. Wetzeliella (Wetzeliella) homomorpha Deflandre & Cookson 1948. Hystrichosphaeridium geometvicuni Pastiels (pars) : 41, pi. 4, figs. 3, 5, 6, 7, 9, 10. 1955- Wetzeliella homomorpha Deflandre & Cookson : 254, pi. 5, fig. 7 ; text-fig. 19. Discussion. The species W. homomorpha is restricted to forms having a peri- phragm with rhomboidal, ovoidal or sub-circular outline and which lacks well developed horns. The processes tend to be concentrated on the ambitus and are generally closed distally. The archaeopyle is intercalary. Deflandre & Cookson (1955) stated that none of the Australian examples contained the internal " cyst " characteristic of Wetzeliella. Their " cyst " formed by the endophragm is in fact present in the forms from the London Clay, but is easily overlooked, since it lies close to and follows the outline of the pericoel. W. homomorpha is therefore a species of Wetzeliella in which the periphragm and endophragm are almost in contact Fig. 50. Wetzeliella {Wetzeliella) tenuivirgiila var. crassoramosa nov. dorsal surface, showing simulate complexes. Tabulation of. 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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