. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. d e f FIGURE 1. Normal first cleavage of Mytilns cdnlis eggs (a-c) and cleavage in a sperm ex- tract (d-f) : a, formation of polar lobe; b, trefoil stage; c, completion of first cleavage; d-f, corre- sponding stages of cleavage in a sperm extract. The cement dissolving activity of sperm extracts is maximal during the process of cleavage. Eggs which have already completed the first cleavage are affected very little. However, if they are allowed to remain in the extract, the A, B, C and D cells, formed by the second cleavage,
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. d e f FIGURE 1. Normal first cleavage of Mytilns cdnlis eggs (a-c) and cleavage in a sperm ex- tract (d-f) : a, formation of polar lobe; b, trefoil stage; c, completion of first cleavage; d-f, corre- sponding stages of cleavage in a sperm extract. The cement dissolving activity of sperm extracts is maximal during the process of cleavage. Eggs which have already completed the first cleavage are affected very little. However, if they are allowed to remain in the extract, the A, B, C and D cells, formed by the second cleavage, become noncoherent and assume a spherical shape. Embryos which are reared in sperm extracts usually develop into a loose mass of ciliated cells. Essentially the same pattern of cleavage and development is obtained if the eggs are allowed to cleave in calcium free sea water. Although there are slight differ- ences in appearance of eggs cleaving in a sperm extract as compared to those in calcium free sea water, it seems reasonable to assume that the sperm extract acts. 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
Size: 1910px × 1308px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
