. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 472 C. M. CHILD. tion at the basal end is indicated by dotting. Fig. 5 is a case of new lateral polarity in a piece some twenty-five mm. in length from the middle of the naked region of a 70-80 mm. animal at a stage four days after operation. The apical hydranth of the piece is the second one developed, the first having been removed two days after section. The apical and the lateral hydranth are so near to- gether that they mutually inhibit tentacle development on the sides facing each other and so have acquired a dorsoventr
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 472 C. M. CHILD. tion at the basal end is indicated by dotting. Fig. 5 is a case of new lateral polarity in a piece some twenty-five mm. in length from the middle of the naked region of a 70-80 mm. animal at a stage four days after operation. The apical hydranth of the piece is the second one developed, the first having been removed two days after section. The apical and the lateral hydranth are so near to- gether that they mutually inhibit tentacle development on the sides facing each other and so have acquired a dorsoventrality with respect to each other. The side of the stem opposite the lateral hydranth shows an outgrowth which later becomes a FIGS. 5-8. Development of new axes from lateral regions of growth determined by injury. Pieces 25 mm. in length from middle of naked region of animals 70-80 mm. Figures are about twice natural size. Figs. 5 and 6, two stages of a piece developing a complete new axis at right angles to the original polarity. Figs. 7 and 8, two stages of a piece which develops a new basal end in relation to both lateral and apical hydranth. Fig. 6 represents the condition of the piece three days later. The two hydranths have now developed separate stems and a new base has arisen opposite the lateral hydranth. This development of a new individual from the apical end basipetally following the localization of the new apical end by the injury is an excellent ex- ample of apicobasal dominance. The localization of an active region by the injury determined a new hydranth, this determined successive stem regions basipetally until finally a .new basal end. 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. ). A
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
