196 Thomas Nomenclature of Measurements. 



We should thus have, counting from before backwards: 



UPPER JAW. LOWER JAW T . 



Cheek-tooth 1 Protus Protid 



2 Deutems Deuterid 



3 Tritus Tritid 



4 Tetartus Tetartid 



5 Pemptus Pemptid 



6 Hectus Hectid 



7 Hebdomus Hebdomid 



To avoid any doubt, I would expressly allocate these names 

 to the permanent teeth of placentals, leaving the names of the 

 marsupial teeth to be settled in accordance with their placental 

 homologies. 



For the milk teeth a further modification would be available 

 by prefixing the syllable Pro- to the names of the respective 

 permanent teeth. We could thus for example in the case of a 

 third lower milk premolar call it the protritid, and so use one 

 word instead of four. 



Of course I have no supposition that this system would ever be 

 frequently or generally used, but I am convinced that in many 

 special cases, and particularly in such descriptions and cata 

 logues of isolated teeth as paleontologists often have to give, it 

 might result in considerable convenience and saving of space. 



