. The Biological bulletin. Biology; Zoology; Marine biology. 234 MARY BLOUNT. section in Fig. 3. The dotted circle, Fig. 2, represents the dis- tance to which the sperm nuclei may migrate peripherally (it is also the peripheral limit of the periblast nuclei, to be explained later), but the accessory cleavage, with a few exceptions, is con-. FiG. 2. Sketch of surface view of a pigeon egg about eight and three fourths hours after fertilization, 4:45 A. M. a, b, c, d, cells of primary cleavage which are shown in section in Fig. 3. xy, the plane of the section in Fig. 3. 1. Accessory cleavage. 2.
. The Biological bulletin. Biology; Zoology; Marine biology. 234 MARY BLOUNT. section in Fig. 3. The dotted circle, Fig. 2, represents the dis- tance to which the sperm nuclei may migrate peripherally (it is also the peripheral limit of the periblast nuclei, to be explained later), but the accessory cleavage, with a few exceptions, is con-. FiG. 2. Sketch of surface view of a pigeon egg about eight and three fourths hours after fertilization, 4:45 A. M. a, b, c, d, cells of primary cleavage which are shown in section in Fig. 3. xy, the plane of the section in Fig. 3. 1. Accessory cleavage. 2. Periblast. fined to the zone just outside the blastomeres of the primary area. A migrating sperm nucleus is shown at the extreme right of Fig. 3. Another sperm-nucleus has migrated under the large blasto- mere a. It is in the central periblast, which will be explained later. A study of the whole series of sections showed a number of nuclei in this position, forming a submarginal circle. They migrate later as far centrally as the margins of the nucleus of Pander, but were never found under the very center of the blastoderm. Fig. 3 is of a section taken through the plane xy of Fig. 2. c b a 2 :li-w. 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 Lillie, Frank Rattray, 1870-1947; Moore, Carl Richard, 1892-; Redfield, Alfred Clarence, 1890-; Marine Biological Laboratory (Woods Hole, Mass. ); Marine Biological Laboratory (Woods Hole, Mass. ). Annual report; HighWire Press. Lancaster, Pa. [etc. ] : Lancaster Press, inc. [etc. ]
Size: 1635px × 1527px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectb, booksubjectzoology
