. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. i88 CARL L. HUBBS. cytologically at earlier stages than this, although he traced the development of the sex-cells from much smaller embryos. At the 15 mm. stage the sexual differences in the form of the anal fin are also apparent in Amphigonoptenis and Micrometrus, although the gonad remains merely a fine strand of tissue; but at the 20 mm. stage the testes have begun to enlarge, and a slight thickening of the radial membranes marks the position of the /£? x^VSNOnf VJ&T VV\( fc$' <\\(?$'£z£ A *rf\^T,a0k 8. /1 • i\\\ «
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. i88 CARL L. HUBBS. cytologically at earlier stages than this, although he traced the development of the sex-cells from much smaller embryos. At the 15 mm. stage the sexual differences in the form of the anal fin are also apparent in Amphigonoptenis and Micrometrus, although the gonad remains merely a fine strand of tissue; but at the 20 mm. stage the testes have begun to enlarge, and a slight thickening of the radial membranes marks the position of the /£? x^VSNOnf VJ&T VV\( fc$' <\\(?$'£z£ A *rf\^T,a0k 8. /1 • i\\\ «'.'(*• ,',V«i" / /.'. * '' 'W "VJM^"-V' «8) / ';.v;-:""' \ * « FIG. 3. Section of testis of a newly-born Amphigonoptenis, showing several stages in spermatogenesis. elaborate gland developed later on the anal fin of the male. The development of these primary and secondary sexual structures thence rapidly proceeds in Amphigonoptenis aurora until birth, at which time the gland on the anal fin is fully elaborated (see Fig. 2), and all stages in spermatogenesis from the primordial germ cells to transforming spermatids at least are evident in the testis, the spermatogonia predominating. Just after birth, the. 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 Marine Biological Laboratory (Woods Hole, Mass. ); Marine Biological Laboratory (Woods Hole, Mass. ). Annual report 1907/08-1952; Lillie, Frank Rattray, 1870-1947; Moore, Carl Richard, 1892-; Redfield, Alfred Clarence, 1890-1983. Woods Hole, Mass. : Marine Biological Laboratory
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
