100 biologcal relations. 



(2) Opisthobranchiata.* 



(3) Hbteropoda.* 



(4) Pteropoda. ConulariidsB — Gonularia. 



Tentaculit i d a — TentacuUtes. 



(5) Stylommatophora.* 



(6) Basommatophora.* 



Class V. — Polyplacopbora.* 



Class VI Scaphora. 



(1) SoLENOCONCHiA. DentaludPB — Bentalium. 



Class YII. — Cephalopoda. 



(1) Tetrabeanchiata. Orthoceratid?e — Orthoceras. 



Ascoceratidie. 

 Cyrtoceratidte — Cyrtoceras. 

 Nautilidte — Nautilus. 

 Trochoceratidse. 

 Clymenidse. 



Goniatitidse — Goniatites. 

 Arcestidse. 

 Tropitidse. 

 Ceratitidse. 

 Cladiscitidse. 

 Pinasocenatidse. 

 Phylloceratidse. 

 Lytoceratidae.* 

 Ptychitidse.* 

 Amaltheidse.* 

 Aegoceratidse.* 

 Harpoceratidse.* 

 Haploceratidse* 

 Stephanoceratidse.* 

 Phragmophora.* 

 Seprophora.* 

 Chondrophora.* 



Class VIII.— Tuiiicata. 



