42 



Study of N. ohaoleta and N. tririttata 



g. Correlation between the^ratio of dianieter to length aiid tlie apical angle of shells of 

 N. ohtoleta from locality 1. 



Diametcr 

 Length ' Angle : 



Mean = 50973. Mean = 10-2292. 



Stfvndard Deviation = 1 '759. Standard Deviation = 2-946. 



CoiTelation = '4787. 

 Tofcvl frequency = 493. 



Angle 



h. Correlation between tbe ratio of diaiuetor to length and the apical angle of shells of 

 N. trivittata froni locality 3. 



Diarueter 



Length ' Angle : 

 Mcan = 6-31 .'58. Mcixn = 5-735. 



Stiuidard Deviation = 1-870. Standard Deviation = 2054. 



Correlation = -7941. 

 Total frequency = 456. 



Angle 



a 



