. Bulletin of the British Museum (Natural History), Geology. FROM GREAT BRITAIN AND FRANCE 273. Fig. 18. Leptodinium egemenii sp. nov. Tabulation and the archaeopyle formation of the holotype (plate 3" is missing). Left, ventral view ; right, dorsal view. xc. 1280. sulcus ; the three other apical plates are more or less uniform in size and smaller than plate 1'. Six precingular plates, without any intercalary plate, together with the apical plates occupy the epitract. Plates 1" and 2" are larger than the others ; plate 3" lost to form the precingular archaeopyle ; plates 4&
. Bulletin of the British Museum (Natural History), Geology. FROM GREAT BRITAIN AND FRANCE 273. Fig. 18. Leptodinium egemenii sp. nov. Tabulation and the archaeopyle formation of the holotype (plate 3" is missing). Left, ventral view ; right, dorsal view. xc. 1280. sulcus ; the three other apical plates are more or less uniform in size and smaller than plate 1'. Six precingular plates, without any intercalary plate, together with the apical plates occupy the epitract. Plates 1" and 2" are larger than the others ; plate 3" lost to form the precingular archaeopyle ; plates 4" and 5" are elongate, 6" is approximately triangular in shape. Six postcingular plates are present : the first (plate 1" ') is small and more or less tetragonal; 2 " ' is narrow and elongate, plate 3" ' is also elongate. Plate 4" ' is largest of the postcingular plates. Plate 5" ' is large and P-shaped as a result of the presence of the posterior intercalary plate 2p. Plate 6" ' is smaller of the post- cingular plates and triangular-shaped. One of the two posterior intercalary plates, ip, is elongate and long ; because of its accommodation, plate 1" ' is reduced. Plate 2p is small and placed posterior to plates 5" ' and 6" '. The single antapical plate 1" " is very small and flattened. The sutures are poorly marked by low crests, their distal edge is always smooth. Remarks. L. egemanii is characterized by its tabulation, lack of an apical horn, and presence of an antapical pericoel. The tabulation was difficult to determine because the crests were poorly marked, and the preservation generally not good. It was observed in the Dorset, Scottish and Le Havre assemblages in moderate abundance. Although it has a Gonyaulacysta-type tabulation, it is not a species of Gonyaulacysta because of the absence of an apical horn, according to the emended diagnoses of Gonyaulacysta and Leptodinium (Sarjeant, 1969) ; it is the
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