1927, Sydney Savory Buckman, Martin Simpson, George Young,Type Ammonites:
[...] disturbance to such a form might produce rapid acceleration in two ways — in shape, fromserpenticone to criocone, in ornament, from tuberculate to costate, that is, costate post-tuberculate.
Coiling isserpenticone or heteromorph, sculpture is of ribbing (almost invariably simple), with external tuberculation in Choristoceratidae. Generally criocone although much of the phragmocone may beserpenticone.
