BIOLOGICAL CLASSIFICATION. 1423 



Family PLECTOCERATID/E Hyatt. 

 Plectoceras Hyatt, Sphyradoceras Hyatt. 



Family LITUITID^; Noetling. 



Ancistroceras Ball, Cyclolituites Remele, Lituites Breynius, Rhynchorthoceras 

 Remele. 



Family HALLOCERATID^E Hyatt. 

 Zitteloceras Hyatt. 



Family NAUTILUS Owen. 

 Nautilus Linnaeus. 



Family LOXOCERATID^E Hyatt. 

 Loxoceras McCoy. 



Family ACTINOCERATID.E Saemann. 



Actinoceras Brown, Cyrtactinoceras Hyatt, Deiroceras Hyatt, Discosorus Hall, 

 Gonioceras Hall, Huronia Stokes, Paractinoceras Hyatt, Tripteroceras Hyatt. 



Family JOVELLANID^E Hyatt. 

 Jovellania Bayle, Tripleuroceras Hyatt. 



Family RIZOCERATID/E Hyatt. 

 Cyrtorizoceras Hyatt, Rizoceras Hyatt. 



Family OOCERATID^E Hyatt. 

 Cyrtoceras Goldfuss, Ooceras Hyatt. 



Family ONCOCERATID^B Hyatt. 

 Cyclostomiceras Hyatt, Eremoceras Hyatt, Meloceras Hyatt, Oncoceras Hall. 



Family POTERIOCERATID^E Foord. 



Clinoceras Mascke, Poterioceras McCoy, Streptoceras Billings. 

 Family TRIMEROCERATID/E Hyatt. 



Hexameroceras Hyatt, Pentameroceraa Hyatt, Septameroceras Hyatt, Trimeroceras 

 Hyatt. 



Family PHRAGMOCERATID^J Hyatt. 



Gomphoceras Sowerby, Phragmoceras Sowerby, Protophragmoceras Hyatt. 



Phyllum ARTHROPODA. 

 Subphyllum BRANCHIATA. 



Class CRUSTACEA. 



Subclass TRILOBITA. 



Order HYPOPARIA. 

 Family AGNOSTID^E McCoy. 

 Agnostus Brongniart, Arthrorachia Corda, Lejopyge Corda. 



Family SHUMARDIID^ Lake. 

 Shumardia Billings. 



Family HARPEDID^J Corda. 

 Eoharpes Raymond, Harpes Goldfuss, Harpides Beyrich. 



