CHAPTER III. 



FERTILITY AND THE SEXES. 1 



"Fertility varies much in individuals of the sunn- specie.-, at different ages 

 and at different stages of the season. 



The sexes in normal fertility are about even. 



"The sexes in lowered fertility show a predominance oi males. 



"The sexes in much lowered fertility are males only. 



"The sexes in the lowest fertility do not appear no offspring. 



"Lowered fertilization shows various decrees, in which development makes 

 a feeble beginning, then halts after a few days. It may run up to within .. 

 hours or days of hatching and then halt. The developmental pi 

 also show different degrees of energy fullness, weakness, irregularities, etc.. after 

 hatching. 



"When fertility is presumably not up to normal, certain colors such as 

 white may be exclusively female. White rings are of both sexes but in hyl 

 between white rings and Japanese turtles the white offspring are all femal 

 (R16) 



Whitman's later studies all of which were in evidence at the time the above 

 was written (1910) clearly show that fertility docs not hear u single. simple rela- 

 tion to sex, but a sort of double relation. Indeed, the double relation which fertility. 

 or at least which "fertility" and "developmental energy," bear to sex would at 

 first sight seem to be contradictor}'. 



Nowhere has Whitman written connectedly or fully on this seeming contra- 

 diction, nor has he written very extensively upon the multitude of facts and illu 

 tions bearing upon the second relation which he discovered that fertility bears to 

 sex. This rather meager exposition of these important results was in keeping \sith 

 a studied policy not to allow himself to write, or definitely to fix opinions, until 

 he had studied the facts from all possible angles of approach. In the records of 

 his last six or seven years of work, however, one finds very frequent allusions 

 a word or a phrase to this second relation which lie found that fertility bear 

 sex, and which at this time he undoubtedly considered as of equal or of even 

 importance than the earlier discovered one. Briefly stated, this second TCMI/ 

 that, in many crosses of very distinct species or of genera, fertility < developmental 

 power) is shown to be highest in the spring and lotirxt hi the tiiitn/nn; and that tnnh 

 offspring predominate in the season of highest fertility, while fcmitlfs J l<ir<;- 

 dominate in the season of lowest fertiliti/. 



But, we ask, how can this fail to contradict the first result compact] 

 above in the second paragraph under this section which lists much lo\\. 

 fertility" as producing "only males"? It is necessary to treat this whole matter 

 immediately and at some length. 



1 The editor has written this chapter; the author's statements are here placed in (imitation mark.- 

 J "Herbst (Arch. f. Entw. Mech. vol. 1>4, No. 2. 1907) Ihiuks that resemblance to father ami mother 



by the size of the copulating nuclei. If female nucleus is at highest level, the resemhlan I maternal 



side. It is sheer superiority in energy." 



' Color and longevity in the offspring arc also, to an appreciable extent, affected i 



and sex; these characters, however, may to advantage be considered elsewhere. EDITOK. 



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