. Senescence and rejuvenescence. Age; Reproduction. INDIVIDUATION AND REPRODUCTION 211. hydranth and another consisting of only the more apical portions (Fig. 8i). In still shorter pieces the proboscis with the sex organs, short tentacles, and mouth may appear in single or biaxial form without any vestiges of other parts (Figs. 82, 83). And, finally, very short pieces give rise only to single biaxial apical portions of the proboscis with mouth and short tentacles (Figs. 84, 8s). Whether the short pieces produce single or biaxial structures, it is at once evi- dent that the more apical regions
. Senescence and rejuvenescence. Age; Reproduction. INDIVIDUATION AND REPRODUCTION 211. hydranth and another consisting of only the more apical portions (Fig. 8i). In still shorter pieces the proboscis with the sex organs, short tentacles, and mouth may appear in single or biaxial form without any vestiges of other parts (Figs. 82, 83). And, finally, very short pieces give rise only to single biaxial apical portions of the proboscis with mouth and short tentacles (Figs. 84, 8s). Whether the short pieces produce single or biaxial structures, it is at once evi- dent that the more apical regions of the tubularian body, , the hydranth, or the apical regions of the hydranth, can develop from any piece of the stem quite independently of the presence of any other part of the body. The conditions necessary for the development of these parts are present in each piece, and the absence of the stem or even the basal portion of the hydranth makes no essential difference in the result. The occurrence of the biaxial structures is as a matter of fact an inci- dental result of the shortness of the pieces. In such pieces the rate of metabohsm at 75 \^ Figs. 75, 76.—Ttibidaria: Fig. 7s, a single individual; Fig. 76, reconstitution in a long piece of stem. the two ends is often practically the same because they repre- sent only a very small fraction of the whole axial 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 Child, Charles Manning, 1869-1954. Chicago, Ill. , The University of Chicago Press
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectreproduction, bookyea
