Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum . Fig. 73. A. Tonohamites koeneni Casey, 1961. SAS Zl 115 from locality 152, Zululand, AptianIV. x 1,3. B, D. Helicancyloceras {Helicancyloceras) \ohimaranitarensis (Collignon, 1962).SAS Z9(5) from locality 168, Zululand, Aptian III-IV. This is an extremely coarsely ribbedspecimen, x 1,6. C. Helicancyloceras {Helicancyloceras) sp. indet. x 1,5. CRETACEOUS FAUNAS FROM SOUTH AFRICA 333. Fig. 74. A-F. Helicancyloceras {Helicancyloceras) vohimaranitraensis (Collignon, 1962). A-C. BMNH C74709 from locality 166, Zululand, Apt
Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum . Fig. 73. A. Tonohamites koeneni Casey, 1961. SAS Zl 115 from locality 152, Zululand, AptianIV. x 1,3. B, D. Helicancyloceras {Helicancyloceras) \ohimaranitarensis (Collignon, 1962).SAS Z9(5) from locality 168, Zululand, Aptian III-IV. This is an extremely coarsely ribbedspecimen, x 1,6. C. Helicancyloceras {Helicancyloceras) sp. indet. x 1,5. CRETACEOUS FAUNAS FROM SOUTH AFRICA 333. Fig. 74. A-F. Helicancyloceras {Helicancyloceras) vohimaranitraensis (Collignon, 1962). A-C. BMNH C74709 from locality 166, Zululand, Aptian III. x 2. D-F. BMNH C79711, same locality and age as above, x 2. 334 ANNALS OF THE SOUTH AFRICAN MUSEUM Material SAS Z8(6), SAS Z8/3, SAS 871D/12, SAS H71D, SAS Z1153, all fromlocality 168 and 152. Aptian III-IV: BMNH C79703-C79712, all fromlocality 166, Aptian III. Description Early stages of growth are helical, either dextral or sinistral, consisting ofabout one and a half to two whorls. The distance between the successive whorlsis extremely variable. After the helical stage coiling becomes planispiral in somespecimens. Ornament in the helix consists of prominent ribs, narrowest and leastprominent on the dorsum, wedge-shaped on the flanks and broadest over theventer. Interspaces on the flanks are about as wide as the ribs. Ribbing over theventer is very variable. At small diameters the ribs are interrupted or weakenedon the venter, in some case
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Keywords: ., bookcentury1800, bookdecade1890, booki, booksubjectnaturalhistory
