40 



Study of N. obsoleta and N. tririttata 



c. Correlation botwecn leiigtli aml immlior of wIkipIs of sliells of iV. obsoleta froni locality 1. 



Length : Nuraber of Whorls : 



Main = 7-856. Meaii = löO'). 



Standard Üeviivtiou = 2'21öl. Standard Deviation = 2"16-12. 



Correlation = -2860. 

 Total frcquency = 493. 



Niimber of Wliorls 



d. Correlation between lengtb and ratio of diameter to lengtb of shells of iV. obsoleta from 

 locality 3. 



Dianieter 

 Length : Length 



Mean = 5-1 36. Mcan = 8-()89. 



Stjuidard Deviation = 1 '902. Standard Deviation = 2'797. 



Correlation= - •2641. 

 Total frequency = 307. 



Index 



