INTRODUCTION. IX 



Terminology of "International" Sterki Stcenberg 



this work. formula. formula. formula. 



Parallel and Twin lamellae la. V 



Angular lamella A 1 V 2 



Parietal lamella P A V 3 



Inf raparietal lamella I . 2 V 4 



Supracolumellar lamella . A t 



Columellar lamella C B A 2 



Subcolumellar lamella . A 3 



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 . 5 G 2 



Suturalfold 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 antwertigo 

 (angular, parietal, inf raparietal, 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, 4 A B Gs, 5, e 



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



