III. CLASS REPTILIA 



Amniota. Allantoidea. Tetrapoda. 



Occipital condyle triple or single. Vertebrae gastro- 

 centrous. 



Ilio-sacral connexion postacetabular. 

 With lungs only ; gills absent. 



1. Sub-CLASS PROREPTILIA 



Temnospondylous : the three pairs of component units of 

 the vertebrae remain separate ; amphicoelous. 

 Eryops. Permian, Texas. 

 Cricotus. Permian, Texas. 



2. Sub-CLASS PROSAURIA 



Amphicoelous, with intercentra, or with movable chevrons. 

 Sphenodon, the only recent genus, has no copulatory organs. 



1. Order Lepospondyli. Chorda persistent, without inter- 

 ruption. Ribs with capitulum and tuberculum. 



Hylonomus. Carboniferous, Nova Scotia. 

 Hyloplesion. Carboniferous, Bohemia. 

 Hylerpeton. Carboniferous, Nova Scotia. 

 ?Smilerpeton. Carboniferous, Nova Scotia. 



2. Order Stereospondyli. Centra of vertebrae solid. 

 With numerous intercentra and chevrons. 



Ribs without tuberculum. Humerus with entepicondylar 

 foramen. 



Numerous abdominal " rib-like " ossifications. Quadrate 

 fixed. 



Two sacral vertebrae. Upper and lower temporal arch. 

 1. Sub -order PROTOROSAURI, Seeley. Protorosaurus. 

 Permian, Germany. 



Palaeohatteria . Permian, Germany. 



?Telerpeton. New Red, Elgin Sandstone. 



? Simaedosaurus. Lower Eocene, France, Belgium. 



