Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum . Fig. 248. Menabites (Delawarella) subdelawarensis CoWignon, 194S. SAM-PCZ5901. Giganticspecimen still fully septate, x 0,34. throughout, higher than wide, with a dorsal zone of impression which embracespreceding whorls up to the lateral tubercle, and a vertical to inward or outwardsloping umbilical wall merging abruptly with the flanks, which remain parallelup to the lateral tubercle at about midflank, and then converge obliquely to avery broad venter. In SAS-Z2100 (Fig. 251) the typical Menabites trituberculate ornam
Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum . Fig. 248. Menabites (Delawarella) subdelawarensis CoWignon, 194S. SAM-PCZ5901. Giganticspecimen still fully septate, x 0,34. throughout, higher than wide, with a dorsal zone of impression which embracespreceding whorls up to the lateral tubercle, and a vertical to inward or outwardsloping umbilical wall merging abruptly with the flanks, which remain parallelup to the lateral tubercle at about midflank, and then converge obliquely to avery broad venter. In SAS-Z2100 (Fig. 251) the typical Menabites trituberculate ornamentis still visible at a diameter of about 40 mm, but thereafter very quickly becomespentatuberculate and rather weak. Ornament after that consists of relativelyweak ribs bifurcating occasionally at the umbilical edge, each bearing five CRETACEOUS FAUNAS FROM SOUTH AFRICA 327. ^ ???# Fig. 249. Menabites (Delawarel/a) subdelawarensis CoWignon, 194S. SAM-PCZ5901. Giganticspecimen still fully septate. Opposite lateral view of Fig. 248. x 0,34. rows of tubercles of which the umbilical (1) and external (5) ones are lateral (2) tubercles are very weak, and the submarginal (3) and marginal (4)ones only slightly stronger. All five rows of tubercles are spaced equidistantlyover the flanks. In this smaller specimen, SAS-Z2100 (Fig. 251), ribs become bolder andmore widely spaced at the largest diameter, whilst the whorl section also appearsto become more inflated. In the larger specimen, SAM-PCZ5901 (Figs 248-250),all ornament weakens at the largest diameter with no distinct strengthening ofthe ribs. 328 ANNALS OF THE SOUTH AFRICAN MUSEUM
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Keywords: ., bookcentury1800, bookdecade1890, booki, booksubjectnaturalhistory
