TRUE— ON THE CLASSIFICATION OF THE CETACEA. 



391 



Professor Abel has described a delphinoid form from the Upper 

 Miocene of Antwerp — Pithanodelphis — in which the atlas and 

 axis are united as in existing genera. It would appear, from this 

 and other evidence, that the family Delphinidge was differentiated 

 as early as the Miocene and that both forms with separate cervicals 

 and forms with united cervicals were then existing. 



The family Saurodelphidse of Abel comprises the single genus 

 Sanrodclphis Burmeister, from the banks of the Parana River, 

 Argentina. The geological horizon is understood to be Pliocene. 

 Professor Abel considers that it cannot be associated at present 

 with any group of toothed whales, but it appears probable from 

 Burmeister's figures that the skull has a maxillary hood and other 

 characters resembling those of Platmiista, and the teeth are also 

 similar in some respects, especially as regards the growth of irreg- 

 ular roots with age, etc. For these reasons, I think it should 

 be assigned to the Platanistidas, at least provisionally. 



The modifications which I have proposed in the classification 

 of the toothed whales are summed up as follows : 



Cetacea. 



Odontoceti. 

 -f- Squalodontidse. 



Physeteridae. . 



Ziphiid^. 

 -f- Eurinodelphidje. 



Iniidse 



Delphinidse .. . . 

 Eurinodelphidse. 



fPhyseterinse. 

 Kogiinse. 



Iniinse. 



Argyrocetinze. 

 Acrodelphinae. 

 Stenodelphinas. 



Delphinapterinse. 



[ Delpl 



iminae. 



