. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. REVISION OF LATE VALANGINIAN CEPHALOPODA 325 Olcostephanus boesei (Riedel) (Fig. 173) is a somewhat compressed species with a moderately wide umbilicus and steep umbilical walls. The latter are ornamented with 7-8 relatively pronounced primary ribs per half whorl, each terminating in a bulla on the umbilical shoulder and giving rise to 4-5 fine, prorsiradiate secondaries. There is commonly 3-4 intercalated ribs between bundles. Parabolae seem to be lacking. This is a finely ribbed species of the asti
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. REVISION OF LATE VALANGINIAN CEPHALOPODA 325 Olcostephanus boesei (Riedel) (Fig. 173) is a somewhat compressed species with a moderately wide umbilicus and steep umbilical walls. The latter are ornamented with 7-8 relatively pronounced primary ribs per half whorl, each terminating in a bulla on the umbilical shoulder and giving rise to 4-5 fine, prorsiradiate secondaries. There is commonly 3-4 intercalated ribs between bundles. Parabolae seem to be lacking. This is a finely ribbed species of the astierianus plexus which was compared with O. sayni (Kilian), from which it was distinguished by its fewer umbilical bullae. It is, therefore, doubtfully separable from O. scissus (Baumberger). Olcostephanus catulloi (Rodighiero) (Fig. 174) is a moderately involute species with a fairly narrow umbilicus. About 25 primary ribs on the outer whorl terminate in prominent bullae on the umbilical shoulder, from which arise 3-5 prorsiradiate secondaries with 1-3 intercalated ribs between bundles. There are 16 secondaries per 3 bullae, with about 125 ribs across the venter of the outer whorl. This species differs from O. astieriformis in being more finely and densely ribbed, with more numerous umbilical bullae. It is, therefore, close to O. sayni. Olcostephanus destefanii (Rodighiero, 1919) is a finely ribbed species, allied to O. sayni, which is yet to be figured. Between 14 and 15 primary ribs terminate in tubercles on the umbilical shoulder and give rise to bundles of fine, slightly flexuous secondaries, with intercalated ribs between bundles. It diners from O. astieriformis in its finer, denser, flexuous secondary ribbing, in which respect it approaches O. sayni gerecseiensis 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 th
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
