1922] 



Griswold: Oyster-shell Scale 



189 



Practically the same thing holds true of the anterior laterals. 

 Here the mode of the apple form is 17, while that of the lilac 

 is 22. In the case of the median group the difference is less 

 marked, yet each form has its mode, that of the apple being 11, 

 while that of the lilac is 13. The greatest contrast is seen in 



Fig. 3. 



liiii 



'zZ S^s^i-^:i- 



6 e 10 IJ 14 16 IS to It U 

 NUMbLJL Of POUEaS in A Ql-OUP 

 LILAC 



Fig. 4. 



NUMBLR- or PbHtJ IN AN INDIVIDUAL 

 AITLIL LILAC 



Fig. 3. Curves showing variation in the number of circumgenital pores of the 

 median group. The curves are based on counts of the pores of 243 

 groups of the apple form and 251 groups of the lilac form. 



Fig. 4. Curves showing variation in the total number of circumgenital pores of 

 all five groups. The curves are based on counts of the pores of 210 

 individuals of the apple form and 220 individuals of the lilac form. 



