INTRODUCTION. IX 



Terminology of "International" Sterki Steenberg 



this work. formula. formula. formula. 



Parallel and Twin laraellas la V t 



Angular lamella A 1 V 2 



Parietal lamella P A V 3 



Infraparietal lamella 2 V 4 



Supracolumellar lamella A t 



Columellar lamella C B A 2 



Subcolumellar lamella A, 



Basal fold B C B 



Infrapalatal folds 3 G 6 - 8 



Lower palatal fold Pi D G 5 



Interpalatal fold 4 G 4 



Upper palatal fold Ps E G 3 



Suprapalatal fold ~> G 2 



Sutural fold 6 G t 



In the second column the letters i and s are added to the 

 initial P to indicate inferior and superior palatals. 



As an example, the teeth of an 8-toothed Vertigo antivcrtigo 

 (angular, parietal, infraparietal, columellar, basal, infra- 

 palatal, lower and upper palatals) would be represented thus: 



Westerlund formula: 3 1 4 



Sterki formula : .A.BC.DE 



Steenberg formula : V 2, 3, A A B G 3, 5, e 



"International" formula: AP. C B. Pi Ps 



