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Emmetrocysta urnaformis
Emmetrocysta urnaformis (Cookson, 1953) Stover, 1975
Originally Cannosphaeropsis, subsequently Polystephanephorus, thirdly (and now) Emmetrocysta.
Holotype: Cookson, 1953, pl. 2, fig. 41-42
Locus typicus: Victoria, Anglesea, Australia
Stratum typicum: Oligocene
Original description: Cookson, 1953, p. 118: Cannosphaeropsis urnaformis
Diagnosis: The type specimen of Cannosphaeropsis urnaformis is a smooth ovoid shell 44x55 Ám with approximately twelve short, broad radially arranged vase-shaped appendages. The latter measure about 20 Ám across the base and about 30 Ám across the rim and are 15-18 Ám long. The walls of the appendages are much perforated, the holes frequently extending from the rim to the prominent annular thickening present at the point of junction of an appendage with the shell-membrane. The rim is entire and slightly fluted. The appendages of this specimen are free from one another. A second example, however, suggests that they may nto have always been so, since two of its appendages are definetely attached to one another by a short and delicate strand. The surface of the shell is finely granular.
Revised description: Stover, 1975, p. 42-43
(annotated) Cyst spherical to ellipsoidal, wall 1 Ám to slightly more than 1 Ám thick, surface uniformly and faintly puncto-reticulate. Processes peritabular, cylindrical to funnel shaped, flared distally; walls smooth to faintly fibrous, unequally perforate with circular, elliptical, and irregularly rounded holes. Process formula gonyaulacacean; 4", 6"", 0c, 5"""-6""", 1p, 1"""", 2-3s (Text-fig. 6). Archeopyle apical, Type (A), operculum free, released as a single piece consisting of the four reflected apical plates. Processes 1" and 4" slender and vase-like; processes 2" and 3" cylindrical and larger than the other two. Individual plates undifferentiated except by processes. Processes on rest of cyst, other than those adjacent to sulcus and on antapical surface, comparatively large and completely isolated from each other (Plate 3, fig. 1). Differences in diameters of processes indicate relative sizes of individual reflected plates. Posterior sulcal, posterior intercalary, and first precingular process (when latter is discernible) of similar size and not appreciably larger anterior sulcal and sixth precingular process. On some specimens smooth trabeculae interconnect anterior sulcal process with process 2"" or 6"", or both, and trabeculae may also extend between first precingular and second postcingular processes. antapical process broadly oval to heart shaped, with slight midventral concavity.
Exclusive of processes, cysts 46 Ám to 55 Ám in diameter; basal diameters fo larger processes 18 Ám to 28 Ám and distal diameters 23 to 38 Ám; basal diameters of smaller processes 6 Ám to 11 Ám and distal diameters 14 Ám to 19 Ám. Process length 17 to 22 Ám; processes on same specimen approximately equal in length.
Variability: The gratest amount of variability appears to be among the sulcal and neighboring processes. On some specimens these processes (1"", 6"", 2""", 6""", as and ps) are clearly separated, each with its own complete ring trabecula. On other specimens interprocess trabeculae connect two or three processes. Most commonly nterconnected processes are 6"", as and 1""; process1"" may be joined to 2""", and the latter to 1p. No specimen was found on which all of these processes are interconnected or with a clearly delimited 1""" process. Surface ornamentation is subdued and varies from puncto-reticulate to scabrate or faintly granulate. Essentially constant features include wall thickness, and the number, relative size, and positions of the peritabular processes.
Originally Cannosphaeropsis, subsequently Polystephanephorus, thirdly (and now) Emmetrocysta.
Holotype: Cookson, 1953, pl. 2, fig. 41-42
Locus typicus: Victoria, Anglesea, Australia
Stratum typicum: Oligocene
Original description: Cookson, 1953, p. 118: Cannosphaeropsis urnaformis
Diagnosis: The type specimen of Cannosphaeropsis urnaformis is a smooth ovoid shell 44x55 Ám with approximately twelve short, broad radially arranged vase-shaped appendages. The latter measure about 20 Ám across the base and about 30 Ám across the rim and are 15-18 Ám long. The walls of the appendages are much perforated, the holes frequently extending from the rim to the prominent annular thickening present at the point of junction of an appendage with the shell-membrane. The rim is entire and slightly fluted. The appendages of this specimen are free from one another. A second example, however, suggests that they may nto have always been so, since two of its appendages are definetely attached to one another by a short and delicate strand. The surface of the shell is finely granular.
Revised description: Stover, 1975, p. 42-43
(annotated) Cyst spherical to ellipsoidal, wall 1 Ám to slightly more than 1 Ám thick, surface uniformly and faintly puncto-reticulate. Processes peritabular, cylindrical to funnel shaped, flared distally; walls smooth to faintly fibrous, unequally perforate with circular, elliptical, and irregularly rounded holes. Process formula gonyaulacacean; 4", 6"", 0c, 5"""-6""", 1p, 1"""", 2-3s (Text-fig. 6). Archeopyle apical, Type (A), operculum free, released as a single piece consisting of the four reflected apical plates. Processes 1" and 4" slender and vase-like; processes 2" and 3" cylindrical and larger than the other two. Individual plates undifferentiated except by processes. Processes on rest of cyst, other than those adjacent to sulcus and on antapical surface, comparatively large and completely isolated from each other (Plate 3, fig. 1). Differences in diameters of processes indicate relative sizes of individual reflected plates. Posterior sulcal, posterior intercalary, and first precingular process (when latter is discernible) of similar size and not appreciably larger anterior sulcal and sixth precingular process. On some specimens smooth trabeculae interconnect anterior sulcal process with process 2"" or 6"", or both, and trabeculae may also extend between first precingular and second postcingular processes. antapical process broadly oval to heart shaped, with slight midventral concavity.
Exclusive of processes, cysts 46 Ám to 55 Ám in diameter; basal diameters fo larger processes 18 Ám to 28 Ám and distal diameters 23 to 38 Ám; basal diameters of smaller processes 6 Ám to 11 Ám and distal diameters 14 Ám to 19 Ám. Process length 17 to 22 Ám; processes on same specimen approximately equal in length.
Variability: The gratest amount of variability appears to be among the sulcal and neighboring processes. On some specimens these processes (1"", 6"", 2""", 6""", as and ps) are clearly separated, each with its own complete ring trabecula. On other specimens interprocess trabeculae connect two or three processes. Most commonly nterconnected processes are 6"", as and 1""; process1"" may be joined to 2""", and the latter to 1p. No specimen was found on which all of these processes are interconnected or with a clearly delimited 1""" process. Surface ornamentation is subdued and varies from puncto-reticulate to scabrate or faintly granulate. Essentially constant features include wall thickness, and the number, relative size, and positions of the peritabular processes.