. Bulletin of the British Museum (Natural History), Geology. 194 KIMMERIDGIAN DINOFLAGELLATES & ACRITARCHS 6" is reduced. The precingular plate i" is long and narrow; plates 2", 3", 4" and 5" are large. One of the specimens observed has a precingular archaeopyle, formed by loss of plate 3". Six postcingular plates occupy the hypotract, together with the single antapical plate and the posterior plates. Plate i"' is quadrate and as small as the adjacent sulcal plate; all the other postcingular plates are relatively large. A crescent-shaped plate, ipv,
. Bulletin of the British Museum (Natural History), Geology. 194 KIMMERIDGIAN DINOFLAGELLATES & ACRITARCHS 6" is reduced. The precingular plate i" is long and narrow; plates 2", 3", 4" and 5" are large. One of the specimens observed has a precingular archaeopyle, formed by loss of plate 3". Six postcingular plates occupy the hypotract, together with the single antapical plate and the posterior plates. Plate i"' is quadrate and as small as the adjacent sulcal plate; all the other postcingular plates are relatively large. A crescent-shaped plate, ipv, separates the sulcus from antapical plate i"". The boundary surrounding the antapical plate i"" bears longer spines than the other sutural spines. All the sutural spines are simple, solid, thin, threadlike. Remarks: This new species is rare, only three specimens being recorded from the following samples: CC 447, RB 219, HC 243 (The first two are from the Baylei Zone, the last from the Pectinatus Zone). It has not been observed in the Middle Kimmeridgian. Two specimens were well preserved, with tabulation and mode of archaeopyle formation easily determinable, but the third was badly preserved. With their long spines distributed like tassels around the antapex, these specimens are different from all previously described proximate dinoflagellate cysts. Gonyaulacysta cf. giuseppei (Morgenroth, 1966) Sarjeant, 1969 Plate 3, figures 3-4, text-figure 4 Description: Cyst subspherical to globular, with the tabulation 4', 6", 6c, 6'", ip and i"". The cingulum is strongly helicoid, laevorotatory, dividing the cyst into two equal parts: the epitract ends in a short apical horn, the hypotract has a conical aspect with very convex antapex. The apical plates combine to form the. Fig. 4. Gonyaulacysta cf. giuseppei (Morgenroth). Showing tabulation and archaeopyle: left, in ventral view; right, in dorsal view. BM(NH) slide x c. Please note
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