Fig. 114 in Scaphites Of The ''Nodosus Group'' From The Upper Cretaceous (Campanian) Of The Western Interior Of North America

Fig. 114. Plot of the ratio of umbilical diameter to shell diameter (UD/D) versus shell diameter (mm) in Hoploscaphites brevis (Meek, 1876) in early (top graph) and later ontogeny (bottom graph; see figs. 110– 112 for illustrations of cross sections on which these graphs are based, and appendix 2, tables 4–6, for a list of measurements). The ratio decreases through most of ontogeny until a shell diameter of approximately 10 mm, after which it remains nearly the same until the formation of the mature body chamber. Filled symbols indicate measurements in the mature body chamber.