. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum . the inner ventrolateral tubercles the ribs project forwards to connectwith outer ventrolateral tubercles close to the siphonal line and are weakly joined acrossthe venter. There is a multiplicity of outer ventrolateral tubercles, unconnected to ribs, sothat on SAM-PCA1892 15 outer ventrolateral tubercles correspond with only sevenlower ventrolateral tubercles (Fig. 21). Occasionally an inner ventrolateral tubercle lacksan accompanying upper ventrolateral. That the inner ventrolateral tubercles represent theseptate b
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum . the inner ventrolateral tubercles the ribs project forwards to connectwith outer ventrolateral tubercles close to the siphonal line and are weakly joined acrossthe venter. There is a multiplicity of outer ventrolateral tubercles, unconnected to ribs, sothat on SAM-PCA1892 15 outer ventrolateral tubercles correspond with only sevenlower ventrolateral tubercles (Fig. 21). Occasionally an inner ventrolateral tubercle lacksan accompanying upper ventrolateral. That the inner ventrolateral tubercles represent theseptate bases of hollow spines is evident from SAM-PCA1892; this specimen preserves13 short, stubby, backwardly directed spines per half whorl impressed in the umbilicalwall or the penultimate whorl. SAM-PCA1885 represents this species in maturity, at a diameter of about 190 mm. Itis compressed, evolute, with a wide, moderately deep umbilicus surrounded by broad,steeply inclined walls and evenly rounded shoulders. The broad flat flank converges 126 ANNALS OF THE SOUTH AFRICAN MUSEUM. Figure 21Morrowites mocamedensis (Howarth). Schematic rib pattern of SAM-PCA1! slightly to the weakly convex, flattened venter, and the costal whorl section issubquadrate, about as wide as high. Ornament comprises about eight prominent umbilicaltubercles per half whorl. These give rise to coarse, distant, almost rectiradiate ribs that arenarrower than the interspaces and ornamented by adorally convex growth striae. Ribsterminate at the ventrolateral shoulder in the swollen bases of hollow horns. At thisgrowth stage intercalatories are lacking and ribbing does not cross the venter. There is arow of small nodate to weakly clavate outer ventrolateral tubercles, some of which occurin the interspaces between horns. Measurements Specimen D H W H/W U SAM-PCA1888 c. 100 c. 38 (38) c. 35 (35) 35 (35) ii 72 27 (38) 24(33) 25 (35) SAM-PCA1892 105 43 (41) c. 40 (38) 32 (30) Discussion The exaggerated ven
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Keywords: ., bookcentury1800, bookdecade1890, booki, booksubjectnaturalhistory
