498 Mr Gompton, On Right- and Left-Handedness in Barley. 



1327 in Guinness' Goldthorpe. With regard to the intermediate 

 ratios it is unwise to dogmatise: but it appears likely that 

 differences should exist between different races of barley in this 

 respect. 



It is difficult to know how to interpret these results. It is 

 interesting, however, to compare the ratios obtained for barley 

 with those recorded in certain other cases of right- and left- 

 handed ness. 



In a paper on the inheritance in man of the mode of clasping 

 the hands, Lutz* states that of the total population investigated 

 6l°/o of the males and 58°/^ of the females habitually cross the 

 right thumb over the left. Here the same percentage occurs as 

 in barley. 



In Anableps anahleps, a Cyprinodont fish, the anal fin is turned 

 either to the right or to the left in different individuals. Garmanf 

 found that about f of the males are dextral, | sinistral : in the 

 females the ratios are reversed. Here again each sex shows a 

 percentage of 60 as between rights and lefts. 



Though the repeated occurrence of this percentage is remark- 

 able, there are cases in which practical equality of rights and lefts 

 is found. For instance, in the males of the Fiddler Crabs, 

 Gelasimus pugilator and 0. pugnax, where the chelae are un- 

 equally developed, Yerkes:|: states that out of nearly 3000 

 specimens he found almost equal numbers of rights and lefts. 



In species of cotton, right- and left-handed plants may be dis- 

 tinguished according as the accessory bud is on the right- or left- 

 hand side of the median axillary bud. Leake § found that nearly 

 equal numbers of both sorts of plants are produced, and considers 

 that right- and left-handedness do not follovv^ the ordinary laws of 

 inheritance. 



In Teleost fishes the optic nerves cross one another at the 

 optic chiasma. Parker|| examined a hundred specimens of each 

 of ten species of teleosts, and found 514 with the nerve from the 

 right eye dorsal, 486 with it ventral. Individual species all 

 approximated fairly closely to the ratio of equality. Larrabee^ 

 investigated the matter further, and found that a random collec- 



* Amer. Naturalist, xlii. 1908, p. 195. My own experience, however, seems to 

 indicate a preponderance of persons who cross the left thumb over the right. 



+ Amer, Naturalist, xxix. 1895, p. 1012. 



J Proc. Amer. Acad, of Arts and Sci. xxxvi. 1901, no. 24. Yerkes considers 

 that the occurrence in equal numbers of right- and left-handed Fiddler Crabs shows 

 that these characters are not hereditary, but are due to chance (p. 440). This is 

 clearly a mistake, for the ratio equaUty in a population may readily occur in cases 

 of Mendelian inheritance : but in any case Yerkes' data are not competent to settle 

 the question of the application of heredity to this instance of right- and left- 

 handedness. 



§ Journ. and Proc. Asiatic Soc. Bengal, v. 1909, p. 23. 



II Bull. Mus. Gomp. Zool. Harvard, xl. 1903, no. 5, p. 219. 



IT Proc. Amer. Acad, of Arts and Sci. xlii. 1906, no. 12. 



