— 122 — 



and then undulate, first in simple curves and afterwards 

 generally in subordinate or smaller flexures. The widest 

 curves occur at their interior extremities. The pattern 

 of inflection resembles somewhat that obtaining in the 

 tusk of Anthracosaurus Russelli (Huxley) *) from the 

 north English coal shale. The prolongations of the pulp 

 cavity in Anthracosaurus however are much narrower 

 and the infolding bands exhibit no secondary undula- 

 tions. But much stress cannot be laid on difl'erences in 

 pattern which varies with position' in each tooth. 

 A smaller striated tooth is partly visible two inches 

 behind the above. Being very imperfectly 

 disclosed it is not susceptible of diagno- 

 sis. On the opposite side of the jaw is a 

 small serial tooth, slender and sharply 

 pointed and slanting backwards and slightly 

 inwards (fig. 4). None of these teeth are 

 vomerine. 



Fi g. 4. 1 am not acquainted with any Permian 



genus of this order of haematocryal vertebrates posses- 

 sing cranial and dental characters precisely correspon- 

 ding with those of the specimen just described and hen- 

 ce submit for it the name of Platyops Rickardi *^), the 

 generic title alluding to its depressed aspect, the specific 

 one to its discoverer, Mr. Rickard, in whose cabinet it 

 now is. 



*) Natur. History Transactions of Northumberland and Durham: 

 Mr. Thos. Atthey on Anthracosaurus Rnss. vol. V. 1877, pi. IX, 

 fig. 4. p. 307 et seq. 



**) тгХатис, flat: шттс, face. 



