CEPHALOPODA. 



101 



No. 206. [499, Cast]. Ammonites heterophyllus, Sow. 



This specimen shows well the elegant and leaf-like foliations which charac- 

 terize tlie gronp '' IleterophylU." It also shows the floor of one of the cham- 

 bers, with the arrangements of the saddles and lobes. From the Upper Lias, 

 Reutlingen, Wurtemberg. Diameter, 7. 



No. 207. Ammonites Humphriesianus, Sow. 



This species belongs to the group "Coro- 

 nati." It is one of the few Ammonites 

 which have preserved the full contour of 

 the front aperture or "mouth" of the shell. 

 From the Lower Oolite, Yeovil, England. 



No. 208. [503, Cast]. Ammonites interruptns, Brug. 



The varieties of this very variable 

 form have been described under many 

 different names, such as A. Delucii, 

 Brong., A. dentatus. Sow., A. Beniiet- 

 tiarms, Sow., A. serrdtus. Sow., etc. 

 From the Lower Cretaceous, St. Flor- 

 entin, France, and now in the Ward 

 Collection, University of Rochester. 



No. 209. [505, Cast]. Ammonites Jason, Reiuccke, 



This beautiful species belongs to the group "Ornati" 

 of Von Buch. The specimens from the Oxford Clay 

 of Christian IVIalford, England, where this was found, 

 are compressed in the marl, but show well two lateral 

 shelly processes developed on each side of the aperture. 

 This feature is found in the young of many species of 

 Ammonites, but is lost on their attaining the adult form. 

 Ward Collection, University of Rochester. 



No. 210. Ammonites Lamberti, Sow. 



From the Oxford Clay (Oolite), Weymouth, England. 



No. 211. Ammonites laticostatus, Sow. 



This is most probably identical with A. cnprlcornus of Schlotheim, and is 

 very typical of the group " Capricorni." In its adult stage, this species loses 

 its characteristic form, and assumes one somewhat resembling A. Bticlui, Sow. 

 In this state it has received various synonyms, but it is best known as A 

 heterogenus. From the Middle Lias, Charmouth, England. 



Original in the 



