. The development of the frog's egg; an introduction to experimental embryology. Embryology. A B C Fig. 5. — Formation of tetrads in testis of Salamandra. (After vom Rath.) spindle (Fig. 5, C). The tetrads next passed toward the equator of the spindle, and there they divided, so that two of each of the four chromosomes passed toward one pole of the cell (as in Gryllotalpa). In this way two new cells are formed with twenty-four chromosomes each. A second division suc- ceeds without an intervening resting-stage, and the number of chromosomes is reduced, so that each cell has twelve chromo- somes
. The development of the frog's egg; an introduction to experimental embryology. Embryology. A B C Fig. 5. — Formation of tetrads in testis of Salamandra. (After vom Rath.) spindle (Fig. 5, C). The tetrads next passed toward the equator of the spindle, and there they divided, so that two of each of the four chromosomes passed toward one pole of the cell (as in Gryllotalpa). In this way two new cells are formed with twenty-four chromosomes each. A second division suc- ceeds without an intervening resting-stage, and the number of chromosomes is reduced, so that each cell has twelve chromo- somes. The cells resulting from the last division, having each twelve chromosomes, differentiate each into a spermatozoon. The second division, according to some workers (Boveri, Hertwig, and Brauer), is the result of a second longitudinal division. But vom Rath holds that this second division in the Amphibia and in Gryllotalpa is the result of a cross-division of. 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
