. The cell in development and inheritance. Cells; Cells. lOO THE GERM-CELLS entiated into a fin-like undulating membrane. The axial filament may be traced through the middle-piece up to the head, at the base of which it terminates in a minute body, single or double, known as the end-hiob, and not improbably representing the centrosome. There is still some doubt regarding the nature and functions of these various parts. The nucleus is proved both by its origin and by its history during fertilization to be exactly equivalent to the nucleus of the mature ^gg. The middle-piece and the tail represe
. The cell in development and inheritance. Cells; Cells. lOO THE GERM-CELLS entiated into a fin-like undulating membrane. The axial filament may be traced through the middle-piece up to the head, at the base of which it terminates in a minute body, single or double, known as the end-hiob, and not improbably representing the centrosome. There is still some doubt regarding the nature and functions of these various parts. The nucleus is proved both by its origin and by its history during fertilization to be exactly equivalent to the nucleus of the mature ^gg. The middle-piece and the tail represent. Fig. 48. —Spermatozoa of fishes and amphibia. [Ballowitz.] A. Sturgeon. B. Pike. C. D. Leuciscus. E. Triton (anterior part). F. Triton (posterior part of flagellum). (7. TPrf/a (anterior part), a. apical body ; (?. end-piece ; y^ fiagellum ; /5. end- knob (? centrosome) ; m. middle-piece; 71. nucleus; s. apical spur. the principal mass of the cytoplasm of the sperm-cell, and the mid- dle-piece is probably to be regarded as merely the thickened basal portion of the flagellum. The principal uncertainty relates to the position of the centro- some. It is certain that in most cases the centrosome or attraction- sphere lies in the middle-piece; for from it the centrosome arises during the fertilization of the &gg, in every accurately known case. In a few cases, moreover, the middle-piece has been traced back to. 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 Wilson, Edmund B. (Edmund Beecher), 1856-1939. New York : The Macmillan company
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectcells, bookyear1896
