. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 88 JAMES O. DAVIS show that the most apparent effect of ultraviolet light is on the neural plate. In- stead of a neural tube forming, a broad flat plate develops. In a few cases the lateral ectoderm appears to be injured as suggested by the dark granular appear- ance of its cells. The groups of cells observed on the surface of the neural plate are probably derived from the lateral ectoderm since the two are very similar in ap- pearance. If this is true, then the isolation of these groups of cells likewise indi- cates that th
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 88 JAMES O. DAVIS show that the most apparent effect of ultraviolet light is on the neural plate. In- stead of a neural tube forming, a broad flat plate develops. In a few cases the lateral ectoderm appears to be injured as suggested by the dark granular appear- ance of its cells. The groups of cells observed on the surface of the neural plate are probably derived from the lateral ectoderm since the two are very similar in ap- pearance. If this is true, then the isolation of these groups of cells likewise indi- cates that the lateral ectoderm is injured. However, the magnitude of this effect 0 14 0 13 012 '006 004 003 002 001. 2400 2500 2600 2700 2800 2900 3000 3100 WAVE LENGTH IN ANGSTROM UNITS FIGURE 3. Photochemical efficiency curve. Inhibition of closure of the neural tube for a distance of at least one-half its length in SO per cent of the embryos. Correction for extinction by vitelline membrane based upon transmission measurements with Hilger spectrograph. (O) and (X) are symbols for experimentally determined doses stronger and weaker respectively than the calculated end-point doses (A). is small; otherwise, the lens and otic vesicle would not develop in an apparently normal manner. Consequently, the effect of radiation on the ectoderm is not nearly as great on the lateral ectoderm as it is on the neural plate. Only mesodermal derivatives which lie directly beneath the ectoderm are in- jured. Although no detectable change in the cellular appearance of the notochord was observed, the cross-section measurements indicate that the notochord is af- fected. The mesenchyme beneath the ectoderm is also injured. This interpreta-. 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. ); Mar
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
