PISCES. 585 



ORDER CROSSOPTERYGIA. 



FAMILY CCELACANTHID^E. Coelacantluis. 



FAMILY* CROSsopTERYGiD^E.Ceratodus, Conchodus, Ctenodus, Heliodus, 



Onycliodus, Peplorhina. 



FAMILY DIPTERID^E. Diplerus, Gnathorhiza, Ptyonodus. 

 FAMILY HOLOPTYCHID^E. Glyptolepis, Holoptychius. 

 FAMILY :i PiiANEnopLEURONiD,E. Phaneropleuroo. 

 FAMILY RHIZODONTID^E. Eusthenopterou, Rhizodus. 



ORDER GINGL.YMODA. 

 FAMILY LEPIDOSTETDJE. Aerolepis, Amblypterus, Eurylepis. 



ORDER PL.ACODERMATA. 



FAMILY CEPIIALASPID.S:. Acanthaspis, Acantholepis, Cephalaspis. 

 FAMILY COCCOSTEID^:. Coccosteus, Dinichthys, Liognathus. 

 FAMILY PTERASPID^E Diplaspis, Palseaspis. 



FAMILY PTERICIITIIYIDJE. Aspidichthys, Bothriolepis, Pterichthys. 

 FAMILY UNCERTAIN. Mycterops. 



ORDER PYCNODONTA.. 



FAMILY PYCNODONTID^E. Platysomus. 

 FAMILY UNCERTAIN. Ectosteorachis. 



SUBCLASS SEL.ACHIA. 

 DIVISION HOLOCEPHALA. 



ORDER CHIMEROIDIDEA. 



FAMILY COIMEROIDID^E. Cyrtacauthus, Liognathus, Machseracanthus, Ptyc- 

 todus, Rhinodus, Rhynchodus. 



DIVISION PLAQIOSTOMATA. 



ORDER SQUALINA. 



FAMILY COCHLIODONTID^E. Chitonodus, Cochliodus, Cymatodus, Deltodopsis, 

 Deltodus, Deltoptychius, Helodus, Orodus, Orthopleurodus, Petrodus, 

 Platvodus, Poecilodus, Psephodus, Sandnlodus, Stenopterodus, Tseuiodus, 

 Tomodus, Trigonodus, Vaticinodus, Xystrodus. The Cochliodontidae 

 commenced at the base of the Subcarboniferous, reached their greatest de- 

 velopment in the same geological system, and only one genus, Orthopleu- 

 rodus, is found as high as the Coal Measures. 



FAMILY HYBODONTID^E. Agassizodus, Apedodus, Bathychilodus, Carcharop- 

 sis, Cladodus, Diplodus, Hybocladodus, Janassa, Lambdodus, Liodus, Me- 

 sodmodus, Orodus, Periplectrodus, Phoebodus, Piisticladodus, Stemmatodus, 

 Thrinacodus, Polyrhizodus. 



FAMILY PETALODONTID^E. Antliodus, Calapodus, Cholodus, Chomatodus, 

 Ctenopetalus, Ctenoptychius, Dactylodus, Desmiodus, Fissodus, Harpaco- 

 dus, Lisgodus, Peltodus, Peripristis, Petalodus, Petalorhynchus, Polyrhi- 

 zodus, Pristodus, Tanaodus, Veuustodus. 



