. The development of the frog's egg; an introduction to experimental embryology. Embryology. 8 DEVELOPMENT OF THE FROG'S EGG [Ch. I vom Rath has found that at the end of the third generation large cells appear with huge nuclei (Fig. 5, B), in which there are twelve groups of chromosomes. Each group or tetrad is composed of four granules. There are, therefore, present forty- eight spherical chromosomes united in groups of four. These tetrads arose from a heterotypic spindle, and in the following- way. As the twelve loops (which are now double, making twenty-four loops) passed toward one pole th
. The development of the frog's egg; an introduction to experimental embryology. Embryology. 8 DEVELOPMENT OF THE FROG'S EGG [Ch. I vom Rath has found that at the end of the third generation large cells appear with huge nuclei (Fig. 5, B), in which there are twelve groups of chromosomes. Each group or tetrad is composed of four granules. There are, therefore, present forty- eight spherical chromosomes united in groups of four. These tetrads arose from a heterotypic spindle, and in the following- way. As the twelve loops (which are now double, making twenty-four loops) passed toward one pole they became much thicker (Fig. 5, A). The middle point of union of each of the twenty-four loops broke (Fig. 5, B), and the portions rounded up, so that there were present forty-eight chromosomes arranged in twelve groups of four chromosomes each (Fig. 5, B). Imme- diately after the formation of the tetrads the groups of chromo- somes arranged themselves along the rays of the achromatic. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Morgan, Thomas Hunt, 1866-1945. New York, The Macmillan company; [etc. , etc. ]
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectembryology, bookyear1
