. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. AXIAL SUSCEPTIBILITY GRADIENTS. 40! ectodermal disintegration occurs in three or four hours dis- integration of the entoderm is usually not complete until one or two hours later or in some cases even a longer time. By returning to sea water after the proper length of time in the. reagent it is possible to stop death at any level of the body and to bring about recovery and further development of the parts still alive. In the blastula it is more or less of the basal portion which remains alive, and this may close up and gastru
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. AXIAL SUSCEPTIBILITY GRADIENTS. 40! ectodermal disintegration occurs in three or four hours dis- integration of the entoderm is usually not complete until one or two hours later or in some cases even a longer time. By returning to sea water after the proper length of time in the. reagent it is possible to stop death at any level of the body and to bring about recovery and further development of the parts still alive. In the blastula it is more or less of the basal portion which remains alive, and this may close up and gastrulate, producing dwarf gastruke with a disproportionately large enteron. In the gastrula stage also partial dwarf gastrulse with large enteron result from partial disintegration and recovery, because the more apical ectoderm may be in large part destroyed while the basal region of the gastrula and the entoderm remain intact. The forms of larvae which develop from these partial basal blastulae and gastrulae will be described in another paper. LATER STAGES. In the early stages of transformation into the pluteus, the gastrula loses its apparent radial symmetry and becomes tri- angular in outline in basal or anal view, the base of the triangle representing the anterior region of the future pluteus. In side view the apex of the gastrula is seen to be shifted toward the anterior end as compared with earlier stages (cf. Figs. 19 and 16). In the further transformation this apical region becomes the oral lobe of the pluteus and the long anal arms develop from the, basal region of the anterior end (Fig. 20).. 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; M
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