. Senescence and rejuvenescence. Age; Reproduction. I04 SENESCENCE AND REJUVENESCENCE. Figs. 14-17.—Reconstitution of pieces of Planaria dorotocephala: Fig. 14, body-outline indicating levels of section; Figs. 15-17, three stages in the reconstitution of an isolated piece. size. Various details of the pro- cess differ according to the size of the piece, the level of the body from which it is taken, the physio- logical condition of the animal, and the environmental conditions, and a limit of size exists which also varies with all these factors; pieces below this Hmit of size do not reproduce co
. Senescence and rejuvenescence. Age; Reproduction. I04 SENESCENCE AND REJUVENESCENCE. Figs. 14-17.—Reconstitution of pieces of Planaria dorotocephala: Fig. 14, body-outline indicating levels of section; Figs. 15-17, three stages in the reconstitution of an isolated piece. size. Various details of the pro- cess differ according to the size of the piece, the level of the body from which it is taken, the physio- logical condition of the animal, and the environmental conditions, and a limit of size exists which also varies with all these factors; pieces below this Hmit of size do not reproduce complete normal animals. The influence of these various factors is evident chiefly in the character of the head, which may range from the normal through a series of teratological forms with a headless condition as the extreme term of the series (Child, '11&, 'lie; see also Figs. 20-23, pp. 111-12). In other species of planarians the process of reconstitution is in general much the same, but with differ- ences in details and in the relation to the various factors mentioned above. The process of reconstitution in these cases differs somewhat from the replacement of a missing part in higher animals. The isolated piece of Planaria does not replace the missing parts in their original condition and size, but develops merely a new head and posterior end and then undergoes an extensive reorganization into a new individual of small size, the size being dependent upon the. 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
Size: 903px × 2767px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectreproduction, bookyea
