220 nil'TYCFlOCEKAS, OorilLUCEKAS, KTC 1 . 



Genus PTYCHOCERAS, d'Orb. 



Shell bent once' upon itself; the two st might portions in contact. 



Eight species. Neoeomian to Cretaceous. Europe ; India ; 

 United States. 

 P. EMERICIANUS, d'Orb. PI. 101, tig. 5o(>. trance. 



Subgenus Diptychoceras, Gabb. 



Three straight liuibs in contact. A Pti/ch.wrax in i.verv 

 respect except that it has an additional limb which incurves, en- 

 veloping both the preceding to a slight degree only. Meek con- 

 siders it doubtfully identical with Ptychoceras. 



Genu^ COCHLOCERAS, Haucr. 



Shell spirally elongated, ' scalariform, strongly sculptured; 

 sutures of septa with several rounded lobes. 



Three species. Alpine Triassic. Hallstatt* Austria. 

 C. FISCHERII. Hauer. PI. 100. tigs 518. 519. 



Genus ANCYLOCERAS, d'Orb. 



Shell at first spiral, discoidal with separated whorls ; after- 

 wards produced at a tangent and then bent back again upon 

 itself like a hook. 



Forty species. Infer. Oolitic, Cretaceous. Europe; South 

 America; United States. 

 A. SPINIGERTJM, Sowb. PI. 100, fig. 52C>. <iault. Folkestone. 



Genus ANISOCERAS, Piutet. 



Shell at first spiral, helicoid, whorls separated, at length more 

 or less prolonged and reflected; transversely ribbed ; sutures of 

 septa with five lobes and saddles, all bipartite. 



Twelve species. Gault to Upper (ireensand, Europe. Creta- 

 ceous, Jurassic, India. 

 A. SAUSSUREANUS, Pictet. PL 100. fig. 528. 



Genus SCAPHITES, Parkinson. 



Shell at iirst closely spiral, involute, at length detached and 

 recurved ; sutures many lobed, lobes foliated. 



Nineteen species. Oolitic, Cretaceous. Europe; India; 

 United States. 

 S. KQI AUS. Sowb. PL 100. lig. 527. Chalk marl. Sussex, Eng. 



