. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. Fig. 18. Peroniceras (Peroniceras) lepeei (Fallot, 1885). A. Whorl section of SAS Z1568. X 1,5. B. External suture of SAS Z1568. C. External suture of SAS A1989. It remains so in SAS Z1568 (Fig. 16A-C), but reverts to being rounded in SAS A1989 over the greater part of the phragmocone and body chamber, with no clearly defined umbilical edge (Fig. 17). On the innermost whorls of SAS Z1568 the flanks are completely smooth up to a diameter of 6 mm, and the venter is fastigiate with a feeble siphonal rid
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. Fig. 18. Peroniceras (Peroniceras) lepeei (Fallot, 1885). A. Whorl section of SAS Z1568. X 1,5. B. External suture of SAS Z1568. C. External suture of SAS A1989. It remains so in SAS Z1568 (Fig. 16A-C), but reverts to being rounded in SAS A1989 over the greater part of the phragmocone and body chamber, with no clearly defined umbilical edge (Fig. 17). On the innermost whorls of SAS Z1568 the flanks are completely smooth up to a diameter of 6 mm, and the venter is fastigiate with a feeble siphonal ridge. Beyond that diameter tubercles appear in the umbilical seam of the succeeding whorl, and at a diameter of 18 mm adult ornament is fully devel- oped. This consists of delicate, concave, prorsiradiate ribs each bearing a clavate tubercle. There are 50 ribs per whorl in SAS Z1568 (Fig. 16 A-C). Ribbing is generally simple but occasional bifurcations occur in SAS A1989 (Fig. 17). Parts of the body chamber of both specimens show dehcate spiral ornament. The venter is tricarinate, with the median keel strongest. The suture is rather simple, with massive saddles and lobes (Fig. 18 B-C).. 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
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
