82 CORRELATED VARIATIONS. 



Another most laborious research undertaken at Pro- 

 fessor Weldon's suggestion is that of H. Thompson,* 

 on the correlation of certain external parts of the 

 prawn, Palcemon serratus. Twenty-two measurements 

 were made on 1000 adult females, and from these the 

 value of Galton's function was calculated for 56 pairs 

 of organs. As might be expected, the degree of corre- 

 lation was highest between the paired organs; e. g. y .94 

 between the right and left squames. Also there was a 

 strong correlation between the terga of adjacent ab- 

 dominal segments, their values ranging between .58 

 and .71. 



Of other recent work on correlation, that by Miss 

 Lee and Professor Pearson f may be briefly alluded to. 

 This consists in a comparison of measurements on cer- 

 tain long bones of about 40 male and 25 female skele- 

 tons of the Aino race (a primitive tribe dwelling in 

 Japan), with corresponding measurements of 50 male 

 and 50 female skeletons of the modern French race. 

 It was found that the transition from the uncivilised to 

 the civilised condition is accompanied by well-marked 

 changes in the sexual relationships; primitive man and 

 woman being more nearly equal in size, variability, and 

 correlation than highly civilised man and woman. 

 Civilised man has gained in size on woman, but this has 

 been accompanied by a relative loss in variability and 

 the correlation of parts. The general result of in- 

 creased civilisation is to increase the absolute size and 

 amount of variation. In females, also, the degree of 

 correlation is increased, but in males this remains sta- 



* Proc. Roy. Soc. , Iv. p. 234. 

 f Proc. Roy. Soc. , Ixi. p. 343. 



