Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum . the characteristicsof Adouliceras, apart from the fact that the spire of A. thomeli tapers much lessrapidly than that of A. adouli which, according to Thomel (personal communi-cation) is grounds for excluding the California form from Adouliceras (Murphy1965: 25). Comparison of the holotype of A. {Ad.) adouli, Figures 3-4, with thespecimen figured by Thomel (1964, pi. 9 (fig. 2)) shows that the size of the initialspire is variable. This is further borne out by the Zululand and Mozambiquematerial to be described below.
Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum . the characteristicsof Adouliceras, apart from the fact that the spire of A. thomeli tapers much lessrapidly than that of A. adouli which, according to Thomel (personal communi-cation) is grounds for excluding the California form from Adouliceras (Murphy1965: 25). Comparison of the holotype of A. {Ad.) adouli, Figures 3-4, with thespecimen figured by Thomel (1964, pi. 9 (fig. 2)) shows that the size of the initialspire is variable. This is further borne out by the Zululand and Mozambiquematerial to be described below. The presence or absence of fine ribs on the hookquoted by Murphy as being a reason for separating Ancyloceras thomeli fromA. (Ad.) adouli is just as variable. It is here proposed to consider the absence of tubercles or stronger ribbingon part of the shaft and the mode of ornament on the early whorls as consti-tuting the main characteristic of Adouliceras. The size of the initial spire isgenerally smaller than that of Ancyloceras 224 ANNALS OF THE SOUTH AFRICAN MUSEUM. Fig. 3. Ancyhteras {Adouliceras) adouli Astier, 1851. BMNH C73806, the original of Astier(1851, pi. 6 (no. 12), pi. 7 (no. 12 bis)), from the Neocomian of Cheiron, Basses Alpes (France).. x 0,45. CRETACEOUS FAUNAS FROM SOUTH AFRICA 225
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Keywords: ., bookcentury1800, bookdecade1890, booki, booksubjectnaturalhistory
