Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum . yatt, 1894 Hyatts family Helicancylidae was revived by Casey (1961: 76, as Helican-cylinae) as a useful subfamily term for those diminutive ancyloceratids inwhich the sculpture is simplified on the terminal hook. The subfamily, as interpreted by Casey, is here accepted with reservation asa useful grouping of three genera only: Tonohamites Spath, 1924, ToxoceratoidesSpath, 1924, and Helicancylus Gabb, 1869, although Acrioceras Hyatt, 1900,Lytocrioceras Spath, 1924, and Leptoceras Uhlig 1883, have also tentatively beenr
Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum . yatt, 1894 Hyatts family Helicancylidae was revived by Casey (1961: 76, as Helican-cylinae) as a useful subfamily term for those diminutive ancyloceratids inwhich the sculpture is simplified on the terminal hook. The subfamily, as interpreted by Casey, is here accepted with reservation asa useful grouping of three genera only: Tonohamites Spath, 1924, ToxoceratoidesSpath, 1924, and Helicancylus Gabb, 1869, although Acrioceras Hyatt, 1900,Lytocrioceras Spath, 1924, and Leptoceras Uhlig 1883, have also tentatively beenreferred to the sub-family. Apart from the fact that the type genus is difficult to interpret (see Casey1961: 77), transitional forms occur, linking the genera. Classification is basedmainly on the mode of ribbing on the body chamber and, to a lesser extent, thepresence or absence of (tri-)tuberculation on the phragmocone. Genus Toxoceratoides Spath, 1924Type species Toxoceras royerianum dOrbigny, 1842 from the Lower Aptian of France. 306 ANNALS OF THE SOUTH AFRICAN MUSEUM. Fig. 58. Australiceras ? sp. ind. B. SAS 54/45 from locality 170, Zululand, Aptian I. x 1. CRETACEOUS FAUNAS FROM SOUTH AFRICA 307 Diagnosis Small forms with ancyloceratid or leptoceratid coiling, probably with aninitial helix. Trituberculate ribs occur on the phragmocone but disappear on therecurved hook. Discussion The genus was discussed extensively by Casey (1961: 79) and little can beadded. Differences between Toxoceratoides and Tonohamites are slight, andtrituberculate forms such as Tonohamites decurrens connect the two genera. The following species were referred to genus Toxoceratoides by Casey(1961): 1. Toxoceratoidesbiplex{vonKoenen) (\902: 3S\, pi 41 (figs 3, lOa-b, lla-b). 2. Toxoceratoides caucasicus (Kasansky) (1914, pi. 1 (fig. 8a-c)). 3. Toxoceratoides fustiformis (von Koenen) (1902: 384, pi. 41 (figs 4-5, 7a-c,9a-b), pi. 53 (figs 8a-b, 9a-b)). 4. Toxoceratoides obliquatus (Young & Bird) (1828:
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