. Carnegie Institution of Washington publication. . 3 4 FIG. 3.—Nucleus at still later stage. Nucleolar fragments separating. Nuclear reticulum, which remains pale-staining, shrunken away from wall. Cytoplasm still dark-staining and now appears as a mixture of fibrillar and alveolar types and contains abundant microsomes. < 1500. FIG. 4.—Nucleus of later stage, showing chromatin products of nucleus scattered through pale reticulm. X 1500. chromosomes. However, both cytological study of the eggs and macroscopical examination of the gonads indicates that the eggs are close to maturation and t
. Carnegie Institution of Washington publication. . 3 4 FIG. 3.—Nucleus at still later stage. Nucleolar fragments separating. Nuclear reticulum, which remains pale-staining, shrunken away from wall. Cytoplasm still dark-staining and now appears as a mixture of fibrillar and alveolar types and contains abundant microsomes. < 1500. FIG. 4.—Nucleus of later stage, showing chromatin products of nucleus scattered through pale reticulm. X 1500. chromosomes. However, both cytological study of the eggs and macroscopical examination of the gonads indicates that the eggs are close to maturation and that the chromosomes have already final characters. For most echino- derms thus far reported on, the somatic number of chromosomes is 36. If these bodies are really chromosomes their number (reduced) here must be several times as many. However, according to Boveri, Echinus inicro- tubcrculatus has only 18 somatic chromosomes, and Tennent1 reports a 1 Tennent, D. H., 1907. Further studies on the parthenogenetic development of the star-fish egg. Biol. Bull., Vol. 13, No. 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 Carnegie Institution of Washington. Washington, Carnegie Institution of Washington
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