. A manual of zoology. Zoology. GENERAL EMBRYOLOGY 139 Conjugation of the Chromosomes.—This reduction in tlie number of chromosomes is explained l)y the plausible supposition (and this is supported by many observations) that the previously separated pjaternal and maternal chromosomes, and chromosomes with the same significance, have united (con- jugation of chromosomes), and accordingly the allelomorphs, the equivalent male and female determinants unite (in our example the determinants for red and white flowers). If in this a complete fusion occur then there would result an inseparable compoun
. A manual of zoology. Zoology. GENERAL EMBRYOLOGY 139 Conjugation of the Chromosomes.—This reduction in tlie number of chromosomes is explained l)y the plausible supposition (and this is supported by many observations) that the previously separated pjaternal and maternal chromosomes, and chromosomes with the same significance, have united (con- jugation of chromosomes), and accordingly the allelomorphs, the equivalent male and female determinants unite (in our example the determinants for red and white flowers). If in this a complete fusion occur then there would result an inseparable compound of characters, but if it be but a juxtaposition, then in the further divisions of the sex-cells, the so-called maturation divisions, botli kinds of determinants, paternal and maternal, would be separated again. The latter would occur in cases following ^lendel's law. The white and red determi- nants, present but only juxtaposed in the male sex cells, would be separated again in one of the two maturation divisions (reduction division) and would be dis- tributed among the resulting cells so that two cells would contain only white, the other two only red determinants (fig. loo). The same would occur in the. Fig. ioo.—Scheme of the maturation divisions of the sex cells to explain the splitting of hybrid characters. It is based on the idea that the splitting, the reduction of the chromosomes, occurs in the first maturation division, while many regard the second as the reduction division. I and II, the first, III and IV, the second maturation di\'ision. C, centrosomes; rf', d'-, centrosomes derived from different parents, which are distributed among separate sex-cells. female sex cell, where at the end of maturation resulting in four cells—three polar globules and the ripe egg—two would contain only white, the other two only red determinants. Thus in the maturation divisions the sex cells lose their hybrid character, and we speak of 'purity of gametes.' Now if such material
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