PRE-JURASSIC TETRAPODS. 



169 



Family Pholidogasterid^:, nov. 



Embolomeri showing a passage to Rachitomi ? With clavicles 

 expanded on the ventral surface. Ventral armour of scutes. 

 (Secondarily aquatic ?) 



Pholidogaster Huxley. Lower Carboniferous, Scotland. 



Family Cricotice Cope. 



Embolomeri with elongated skulls. Clavicles expanded on the 

 ventral surface. Ventral armour of small scutes. (Secondarily 

 aquatic ? ) 



Cricotus Cope. Artinskian, Texas, and ? U. Coal Measures, 

 Illinois. 



Embolomeri incerta sedis. 



Diplovertebron Fritsch. L. Permian, Bohemia. 

 JSFummulosaurus ,, ,, 

 Macromerium ,, ,, 



Spondylerpeton Moodie. U, Carboniferous. Illinois. 



Grade RACHITOMI Cope. 



Labyrinthodonts with ossified basioccipital and basisphenoid. 

 Occipital condyle triple or double. Pterygoids usually with a 

 medium-sized palatal part, interpterygoid vacuities of medium 

 to large size. Pterygoids articulating with both parasphenoid 

 and basisphenoid. Tabulars and dermo-supraoccipitals with 

 occipital flanges. Paroccipital always visible from behind. 



Vertebra? rachitomous, i. e., with small paired pleurocentra 

 and half-moon shaped intercentra. 



Grade STEREOSPONDYLI Cope. 



Labyrinthodonts with reduced basioccipital and basisphenoid. 

 Occipital condyle double. Pterygoids with a reduced palatal 

 ramus, interpterygoid vacuities large to very large. Pterygoids 

 supported by the parasphenoid. Exoccipital meeting the occi- 

 pital flange of the tabular so as to hide the paroccipital in an 

 occipital view. 



Vertebras stereospondylous, i. e., with very reduced or absent 

 pleurocentra and enlarged intercentra. 



I have discussed the classification of the grades Rachitomi and 

 Stereospondyli in very great detail in a paper which will, I hope, 

 soon be published ; it is therefore unnecessary to reproduce the 

 division into families on the present occasion. 



Super-Order PHYLLOSPONDYLIA Credner. 



Small, very highly specialised Batrachia with a roofed skull, 

 palate with very widely open interpterygoid vacuities, palatines 

 and lower jaw very reduced. Coracoid and pubis not ossified. 

 Four-fingered hand. Ventral armour of small round scutes. 



Proc. Zool. Soc— 1917, No. XII. 12 



