. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. SEX-CHROMOSOMES OF PSYCHID/E. 403 point of fact, I have two perfect pairs of daughter-plates, each with 29 chromosomes (see Table I., nos. 33, 34). No X-chro- mosome is present in these cases. If we leave these out of account there remain 35 females and 25 males, a sex-ratio of : I in favor of the female, that is to say, exactly the ratio to be expected from observations on the maturation-phenomena in the Tornow race. Possibly the embryos with 58 chromosomes may have arisen by the development of unfertilized eggs. 2. Fit
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. SEX-CHROMOSOMES OF PSYCHID/E. 403 point of fact, I have two perfect pairs of daughter-plates, each with 29 chromosomes (see Table I., nos. 33, 34). No X-chro- mosome is present in these cases. If we leave these out of account there remain 35 females and 25 males, a sex-ratio of : I in favor of the female, that is to say, exactly the ratio to be expected from observations on the maturation-phenomena in the Tornow race. Possibly the embryos with 58 chromosomes may have arisen by the development of unfertilized eggs. 2. Fitmea casta PALL. The equatorial plate of the first maturation-division in the egg shows 31 chromosomes. One of these must be univalent, for the daughter-plates show in some cases 31 chromosomes, in others 30. As in Tal<zporia, an X-chromosome is present but strange to say it fails to lag behind the autosomes and passes together with them to one spindle-pole. Fig. 23, from a perfect plate with 30 chromosomes, clearly shows the natural size-rela- tions. Figs. 19 and 20, 21 and 22, 24 and 25 are three pairs of daughter-plates, from the interkinesis, in which the chromosomes are perfectly clear and well-separated; but unfortunately the plates lay obliquely, so that the photographs seem to show certain fusions which do not really exist. Text-figure I shows the same. TEXT FIG. 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
