. The elements of experimental embryology. Embryology, Experimental; Embryology. 336 FIELDS AND GRADIENTS IN NORMAL ONTOGENY produced, which are entirely composed of endoderm, with the usual exception of a tiny button at the apical end of the large endo- dermal vesicle. When the treatment is discontinued at the 24-hour stage, only moderate effects, resulting in exogastrulae, are En. Fig. 156 Differential inhibition of the ectoderm in sea-urchin larvae reared in water to which lithium salts are added. Progressive stages of inhibition with increasing concentrations of lithium, a, is an e
. The elements of experimental embryology. Embryology, Experimental; Embryology. 336 FIELDS AND GRADIENTS IN NORMAL ONTOGENY produced, which are entirely composed of endoderm, with the usual exception of a tiny button at the apical end of the large endo- dermal vesicle. When the treatment is discontinued at the 24-hour stage, only moderate effects, resulting in exogastrulae, are En. Fig. 156 Differential inhibition of the ectoderm in sea-urchin larvae reared in water to which lithium salts are added. Progressive stages of inhibition with increasing concentrations of lithium, a, is an exogastrula; e, is completely endodermised. Ek. ectoderm; En. endoderm; Mz. mesenchyme; Pz. pigment cells; Zr. clump of cells at base of exogastrulated gut. (After Herbst, from Schleip, Determina- tion der Pri?mtiventzvicklimg, 1929, fig. 323, p. 505.) When the treatment is not begun until the late blastula or gastrula stage, death soon ensues, but without any modification of the pro- portions of the germ-layers, indicating that this is determined by the mid-blastula stage. It may be suggested that this result is in part due to differential. 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 Huxley, Julian, 1887-1975; De Beer, Gavin, Sir, 1899-1972. New York [Hafner Pub. Co. ]
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Keywords: ., bookcentury1900, bookcollectionbiodiversi, booksubjectembryology
