. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 264 SZMANT-FROELICH, YEVICH AND PILSON. FIGURE 10. Photomicrographs of various stages in the embryonic development of Astrangia danae. A. Unfertilized egg wth eccentric nucleus. B. First cleavage proceeds from animal to vegetal pole. C. First division complete; notice small protuberances being pinched off at vegetal pole. D. Psuedospiral arrangement of blastomeres after second division. E. Irregularly shaped embryos resulting from nonsynchronous third and fourth divisions. F. Embryo of around 20 blastomeres, with large blast
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 264 SZMANT-FROELICH, YEVICH AND PILSON. FIGURE 10. Photomicrographs of various stages in the embryonic development of Astrangia danae. A. Unfertilized egg wth eccentric nucleus. B. First cleavage proceeds from animal to vegetal pole. C. First division complete; notice small protuberances being pinched off at vegetal pole. D. Psuedospiral arrangement of blastomeres after second division. E. Irregularly shaped embryos resulting from nonsynchronous third and fourth divisions. F. Embryo of around 20 blastomeres, with large blastocoele. G. Sixty-four cell stage; blasto- meres still rounded. H. Blastula stage; blastomeres compressed. I. Planula stage, showing apical tuft of cilia and oral pore. Abbreviations: AP—animal pole; AT—apical ciliary tuft; B—blastocoele; N—nucleus; OP—oral pore. Scale bars are 10 /xm. Few eggs remained in the gonads. By mid-September, however, stage I and II oocytes began to appear in the mesenteries again. Although some of these oocytes developed as far as stage IV, they were never as numerous and they never attained the size of the mid-summer oocytes. As with the male colonies, there was no evi-. 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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