554 



Chas. W. Hargitt. 



given the number of rhopalia, while the number of specimens are 

 arranged in the squares. While in general there is a very close 

 correlation between these organs it will be seen that there are not 

 infrequent departures from this rule, or in other words absence 

 of correlation. For example, two specimens were found having 

 only seven rhopalia while there were eight marginal lobes. Like- 

 wise there will be seen to be five specimens having more rhopalia 

 than marginal lobes in normal octamerous individuals. A simi- 



Table II. — Showing Correlations of Oral and Gastric Lobes. 

 ORAL LOBES. 



lar condition of variation is shown in specimens having seven, 

 nine, ten, eleven, and twelve marginal lobes and rhopalia. 



A curve constructed by which to portray even more graphically 

 the facts would involve the following factors:^ 



Marginal Lobils. Rhopalia. 



Mean variation 8.396 8.379 



Standard deviation 896 .872 



Coefficient of variability 1 .06 1 .04 



Probable error of mean ± -015 ± -002 



Probable error of standard deviation ± .01 1 i .01 1 



Average deviation 626 .641 



*For calculating the factors of this curve I am under obligations to my colleague, Dr. Smallwood. 



