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THE AMERICAN NATURALIST [Vol. XLV1II 



sweet seeds, 3 with horny and waxy seeds, 19 with horny, 

 sweet and waxy seeds and 2 all sweet. 



The two all sweet ears are entirely outside the expected. 

 Their appearance may be explained on the assumption 

 that seeds classed as horny in 1912 were in reality sweet. 

 No microscopical examination of the starch was made 

 and the seeds were classified on their appearance, 

 wrinkled seeds being classed as sweet and smooth seeds 

 as horny. The separation of horny from sweet seeds is 

 more difficult to make than waxy from either horny or 

 sweet. 2 



There were, however, very few doubtful seeds in the 

 second xenia generation and in suggesting this interpre- 

 tation, we may with some propriety be accused of attempt- 

 ing to explain away "green balls." 3 



The two all sweet ears were descendants of an ear Dh 

 221-2, which showed an excess of horny seeds and a 

 deficiency of sweet. The expected number of sweet seeds 

 in Dh 221-2, which had a total of 493 seeds, was 123 and 

 only 106 were classified as sweet. If this deviation re- 

 sulted from a faulty classification, that is, if some of the 

 sweet seeds failed to show the characteristic wrinkled 

 exterior, we might expect that about 17 of the 300 seeds 

 classed as horny would produce ears with all sweet seeds. 

 Eleven of the ears secured from horny seeds in 1913 were 

 descendents of this ear. 



The remaining 28 ears from horny seeds are distributed 

 among the 3 classes in reasonably close agreement to the 

 expected. Measured by Pearson's formula for the good- 

 ness of fit, 4 it appears that such a deviation might be 

 expected once in about twenty times. 



2 The difficulty of distinguishing between sweet and starchy seeds in 

 crosses where the starchy variety has small seeds has been pointed out by 

 East and Hays, "Inheritance in Maize," Bull. 167, Conn. Ag. Exp. Sta., 

 1911, p. 40. 



3 Pearson, K., and Heron, D., "On Theories of Association," Biometrika, 

 IX, pp. 309-314. 



* Phil. Mac,., Vol. L, 1900, pp. 157-175. The application of Pearson's 



