1895.] into the Measurable Characteristics of Plants, fyc. 375 



Table V. Frequency of all observed Deviations from the Mean 

 Length of the Right Dentary Margin in 8020 Female Crabs r 

 Young and Adult, from Plymouth. Deviations in terms of 

 the Modulus. 



The symmetry of these results is fairly good, the number of posi- 

 tively abnormal individuals being 4030, the number of negatively 

 abnormal 3990. The sum of the squares of the negative deviations 

 is 2145*5 ; the sum of the squares of the positive deviations being 

 2099-9 a difference of about 2 per cent. This difference is greater 

 than in the case of the frontal breadths ; but a reference to the table 

 will show that the removal of a single individual, namely, the indi- 



