Fig. 2From: The internal structure of varices and constrictions in Jurassic and Cretaceous ammonoid shellsOccurrence of pre-adult varices and constrictions in ammonoids in the Jurassic and Cretaceous (modified from Rouget et al. 2004). Grey superfamilies with constrictions. Black-and-white pattern superfamilies with varices and constrictionsBack to article page