Heredity and sex . ^ must be produced from parts of the body thathave never produced them before, and it is unlikelytherefore that any preparation for this casualty wouldhave been made. The location and differentiation HERMAPHRODITISM 169 of these organs may seem to depend on the same^ relation-of-the-parts-to-each-other on which allsomatic differentiation depends. If this were the correct interpretation then the prob-lem of sex in hermaphrodites would appear in a differenthght from the problem of sex in species in which malesand females occm*, and the appeal would be made to anentirely differ
Heredity and sex . ^ must be produced from parts of the body thathave never produced them before, and it is unlikelytherefore that any preparation for this casualty wouldhave been made. The location and differentiation HERMAPHRODITISM 169 of these organs may seem to depend on the same^ relation-of-the-parts-to-each-other on which allsomatic differentiation depends. If this were the correct interpretation then the prob-lem of sex in hermaphrodites would appear in a differenthght from the problem of sex in species in which malesand females occm*, and the appeal would be made to anentirely different principle. In cases where a sexual generation alternates witha hermaphroditic generation, the problem of the two. Fig. 86. —Rhabditis nigrivernjsa, male (left) and female (right). (After Leunis.) ^ sexes reappears. There is but one case in animalsthat has been adequately worked out. A nematodeworm, Rhahditis nigrovenosa, hves as a parasite inthe lungs of frogs. It is an hermaphrodite. Itseggs give rise to another generation that hves in mudand slmie. In this generation two kinds of individualsare present — true males and females (Fig. 86). Thefemales produce eggs, that are fertihzed, and develop 170 HEREDITY AND SEX into the hermaphrodites which find their way againinto the lungs of frogs. Boveri and Schleip have worked out the historyof the chromosomes in this case. The cells of the X---h-
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Keywords: ., boo, bookcentury1900, bookdecade1910, booksubjectsex, bookyear1913
