The cell in development and inheritance . tration of the rings. E. The rings broken up intotetrads. F. First division-figure established. heterotypical mitosis (p. 86). The breaking of the ring into fourparts involves, first, the separation of these two halves (correspondingwith the original longitudinal split), and second, the transverse divisionof each half, the latter being the reducing division of number of primary rods, from which the rings arise, is one-halfthe somatic number. Hence each of them is conceived by Vom Rath,Hacker, and Riickert as bivalent or double ; as re
The cell in development and inheritance . tration of the rings. E. The rings broken up intotetrads. F. First division-figure established. heterotypical mitosis (p. 86). The breaking of the ring into fourparts involves, first, the separation of these two halves (correspondingwith the original longitudinal split), and second, the transverse divisionof each half, the latter being the reducing division of number of primary rods, from which the rings arise, is one-halfthe somatic number. Hence each of them is conceived by Vom Rath,Hacker, and Riickert as bivalent or double ; as representing twochromosomes united end to end. This appears with the greatestclearness in the spermatogenesis of GryUotalpa (Fig. 122). Here 250 REDUCTION OF THE CHROMOSOMES the spireme-thread splits lengthwise before its segmentation into then divides transversely to form six double rods (half the usualnumber of chromosomes), which open out to form six closed become small and thick, break each into four parts, and thus. 9fi°o
Size: 1859px × 1345px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectcells, bookyear1902
