The cell in development and inheritance . Fig. 141. — First type of maturation in the parthenogenetic egg oi Artemia. [Brauer.] A. The first polar spindle; the equatorial plate contains 84 tetrads. B. C. Formation of thefirst polar body; 84 dyads remain in the egg, and these give rise to the egg-nucleus, shown in Appearance of the egg-centrosome and aster. E. G. Division of the aster and formationof the cleavage-figure; the equatorial plate consists of 84 apparently single but in reality bivalentchromosomes. this arise eighty-four thread-like chromosomes, and the same numberappears in lat
The cell in development and inheritance . Fig. 141. — First type of maturation in the parthenogenetic egg oi Artemia. [Brauer.] A. The first polar spindle; the equatorial plate contains 84 tetrads. B. C. Formation of thefirst polar body; 84 dyads remain in the egg, and these give rise to the egg-nucleus, shown in Appearance of the egg-centrosome and aster. E. G. Division of the aster and formationof the cleavage-figure; the equatorial plate consists of 84 apparently single but in reality bivalentchromosomes. this arise eighty-four thread-like chromosomes, and the same numberappears in later cleavage-stages. {b) It is the second and rarer mode that realizes Boveris concep-tion (Fig. 142). Both polar bodies are formed, the first removingeighty-four dyads and leaving the same number in the egg. In theformation of the second, the eighty-four dyads are halved to form MATURATION OF PARTHENOGENETIC EGGS 283 two daughter-groups, each containing eighty-four single these groups remai7i in the egg, and each gives
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectcells, bookyear1902
