Archive image from page 26 of The development of the human. The development of the human body : a manual of human embryology . developmentofhum00mcmu Year: 1914 SPERMATOGENESIS 15 supposed case that is being described (Fig. 7, sc1). The further history of these chromosomes indicates that each is composed of four elements more or less closely united to form a tetrad, and during mitosis each tetrad divides into two dyads, four of which will there- fore pass into each secondary spermatocyte. These cells (Fig. 7, sc2) Fig. 7.—Diagram Illustrating the Reduction of the Chromosomes During Spermat
Archive image from page 26 of The development of the human. The development of the human body : a manual of human embryology . developmentofhum00mcmu Year: 1914 SPERMATOGENESIS 15 supposed case that is being described (Fig. 7, sc1). The further history of these chromosomes indicates that each is composed of four elements more or less closely united to form a tetrad, and during mitosis each tetrad divides into two dyads, four of which will there- fore pass into each secondary spermatocyte. These cells (Fig. 7, sc2) Fig. 7.—Diagram Illustrating the Reduction of the Chromosomes During Spermatogenesis. sc1, Spermatocyte of the first order; sc2, spermatocyte of the second order; sp, spermatid. undergo division without the usual reconstruction of the nucleus and each of the dyads which they contain is halved, so that each sper- matid receives a number of single chromosomes equal to half the number characteristic for the species (Fig. 7, sp). This account of the behavior of the chromosomes during sper-
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