. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. Fig. 71. Mortoniceras {Angolaites) gregoryi (Spath). The holotype, from the uppermost Albian at Catumbella, BMNH C20O66. x 1. Description The shell is very evolute, compressed, with a wide, shallow umbilicus (42-47% of the diameter). The umbilical walls are gently rounded and the flanks are slightly convex intercostally, converging somewhat towards the venter, with greatest width slightly above the umbilical shoulder. Ribs begin very weakly on the umbilical wall and pass radially outwards to the umbi
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. Fig. 71. Mortoniceras {Angolaites) gregoryi (Spath). The holotype, from the uppermost Albian at Catumbella, BMNH C20O66. x 1. Description The shell is very evolute, compressed, with a wide, shallow umbilicus (42-47% of the diameter). The umbilical walls are gently rounded and the flanks are slightly convex intercostally, converging somewhat towards the venter, with greatest width slightly above the umbilical shoulder. Ribs begin very weakly on the umbilical wall and pass radially outwards to the umbilical shoulder where they terminate in fairly prominent bullae, about seventeen per whorl. Each bulla gives rise to one to two flank ribs, with frequent intercalatories which become more abundant in maturity. Across the flanks the ribs are prorsiradiate and all are ornamented with closely spaced double ventro- lateral tubercles. There are thirty-nine ventrolateral tubercles on the outer whorl, and the upper ventrolateral tubercles are spirally notched. The venter is moderately narrow, with shallow sulci on either side of the siphonal 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 South African Museum. Cape Town : The Museum
Size: 1422px × 1757px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
