. Bulletin of the Natural Histort Museum. Geology series. 80 This genus, however, as well as being generally more evolute, shows a different ontogeny (see Zaborski 1987: 43 for a discussion). Its juvenile whorls characteristically show strong ribs arising in twos or threes from umbilical tubercles, elements of this ornament persisting to varying stages in later ontogeny. The present material shows an ontogenetic development typical of Vascoceras rather than Fagesia. Barber (1957) proposed two species of Fagesia from north-eastern Nigeria but pointed out that they were both intermediate with Va
. Bulletin of the Natural Histort Museum. Geology series. 80 This genus, however, as well as being generally more evolute, shows a different ontogeny (see Zaborski 1987: 43 for a discussion). Its juvenile whorls characteristically show strong ribs arising in twos or threes from umbilical tubercles, elements of this ornament persisting to varying stages in later ontogeny. The present material shows an ontogenetic development typical of Vascoceras rather than Fagesia. Barber (1957) proposed two species of Fagesia from north-eastern Nigeria but pointed out that they were both intermediate with Vascoceras. These forms are problematical, being based on a very few specimens of unknown stratigraphical provenance. F. simplex Barber (1957: 27, pi. 8, fig. 1; pi. 29, figs 4, 5) has a simple suture and is best regarded as an indeterminate Vascoceras. F. involuta Barber (1957: 27, pi. 9, fig. 3; pi. 29, figs 6, 7) has a complex suture, narrow umbilicus and highly depressed whorls; the early growth stages are unknown. It may be most closely related to V. globosuni globoswn. Vascoceras globosum proprium (Reyment, 1954^) Figs 45-47,49,55-57,63, 64 1920 1920 1931 1954/7 1954/7 1954/7 Vascoceras angermanni Bose: 217, pi. 16, figs 1, 3 (only); pi. 17, fig. 1. Neoptychites aff cephalotus (Courtiller); Bose: 221, pi. 18,figs3, 10, 13. Thomasites sp. Adkins: 56, pi. 2, figs 16, 17. Pachyvascocerasproprium Reyment: 258, pi. 5, figs la, b; text-fig. 3d. Pachyvascoceras proprium plenum Reyment: 258, pi. 5, fig. 5; text-figs 3c, 6. Gombeoceras?bulbosum Reyment: 263, pi. 4, figs 2a, b; ZABORSKI text-figs 3g, 9. 71957 Vascoceras ellipticum Barber: 17 (pars), pi. 6, figs 1 a, b; pi. 26, fig. 11 (only). 1957 Vascoceras globosum globosum (Reyment) Barber: 21 (pars), pi. 7, fig. 1. 1957 Vascoceras globosum plenum (Reyment) Barber: 23, pi. 7, fig. 2; pi. 9, fig. 2; pi. 28, figs 3-5. 1957 Vascoceras globosum proprium (Reyment) Barber: 25, pi. 7, fig. 3; pi. 28, figs 6, 7. 1957 Vascoceras glo
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