Fig. i6. A, Dimetrodon incisivus Cope. Pelycosaur: left mandible, outer side. B, 

 Dimetrodon incisivus Cope. Pelycosaur: left mandible, inner side. C, Dimetrodon 

 incisivus Cope. Pelycosaur: right mandible, inner side. D, Labidosaurus hamatus 

 Cope. Cotylosaur: right mandible, inner side. E, Labidosaurus hamatus Cope. 

 Cotylosaur: right mandible, outer side. 



