. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 140 F. M. SUMMERS cell of the original colony. In this respect they were similar to the extensive cut-back types and subject to the same technical limitations. The regulative activity of the zooids of the second and third order regenerates in progressively cut colonies was similar in most respects to that evoked after simple cut-offs. In each of the nine cases studied the same morphological pattern and, as far as the limited number of cases permit judgment, similar developmental rates obtained after the second and third oper
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 140 F. M. SUMMERS cell of the original colony. In this respect they were similar to the extensive cut-back types and subject to the same technical limitations. The regulative activity of the zooids of the second and third order regenerates in progressively cut colonies was similar in most respects to that evoked after simple cut-offs. In each of the nine cases studied the same morphological pattern and, as far as the limited number of cases permit judgment, similar developmental rates obtained after the second and third operations. Incomplete Section of the Stalk.—In a few cases out of many trials a local injury to the neuro-muscular cord was effected without destroy- ing the continuity of the cortical hyaline stalk substance. A re-. FIG. 4. A. Development after two successive operations (54 hours after the first cut). The original axis lies on the right. The severed peduncle of the regener- ated terminal macrozooid may be seen near the base of the second regenerate. Axial microzooid 1C was badly parasitized; it dropped away soon after the drawing was made. X 250. B. Schematic representation of A. The cuts are indicated by arrows. *Para- sitized zooid. quisite degree of compression between the needles caused the cord to break down into a series of irregular protoplasmic droplets, some of which appeared to be independent of any attenuated membranous connectives. Several interesting facts we're brought out by this type of opera- tion. The severed part of the neuro-muscular cord did not recover from the injury, the structural or functional cont inuity between the separated parts was not re-established. After the injury there was no subsequent degeneration of the cord in either proximal or distal parts. The functional unity of the whole was permanently impaired. The. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - colo
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
