Atavistic Races. 481 



the several generations of this race with a true syncotyl- 

 ous race (see the table on page 470), we only tind in most 

 of them an oscillation within much wider limits. 



The hemi-syncotyls are, therefore, only variants of 

 the syncotylous race. 



§ 12. ATAVISTIC RACES. 



Although the atavistic specimens of Hclianthiis an- 

 nuits syncotylciis are exactly similar to the normal seed- 

 lings of the ordinary sunflower, they nevertheless belong 

 to the syncotylous race and do not depart from it. With 

 regard to their visible characters they are aberrant forms; 

 with regard to their progeny, however, simply extreme 

 minus variants ; but the latter is true only on the average, 

 and not for the particular atavists whose values often 

 approach those of the best syncotyls, and not infrequently 

 exceed the mean of the race. 



If tlie intermediate race were not pure we should, of 

 course, still be able to select the corresponding half race 

 from it. But after it has once been purified by selection, 

 this is no longer possible. A syncotylous intermediate 

 race can no more give rise to a half race than a tricotylous 

 half race can be transformed by selection into an inter- 

 mediate race (see Amarantus and Scroplmlaria, pp. 398 

 and 407). In the years 1890, 1891, 1892 and 1804. I 

 made extensive cultures of atavists derived from my 

 syncotylous race and also from my hemi-syncotylous 

 race, and determined their hereditary values for one or 

 two generations. In these experiments curves were ob- 

 tained which w^ere not asymmetrical, with a peak at one 

 end, but wxre flattened curves, extendino: over the whole 

 length of the base line. Thus, for instance, I obtained 

 from a dozen atavists from the seeds of the seed-parent 



