. The elements of experimental embryology. Embryology, Experimental; Embryology. a b Fig. 13 The expanding growth-tendency of the presumptive epidermis of the Urodele embryo, a. Two ventral gastrula-halves grafted together, the epidermis of each of which is thrown into ridges and folds in vainly trying to overgrow the other. b. The same, 16 hours later, showing intensification of ridges and folds. (From Spemann, Arch. Entzvmech. cxxiii, 1931.) diameter. Thirdly, the cells just beneath the marginal zone in the dorsal meridian have the tendency to invaginate and form a pit-like depression. Norma
. The elements of experimental embryology. Embryology, Experimental; Embryology. a b Fig. 13 The expanding growth-tendency of the presumptive epidermis of the Urodele embryo, a. Two ventral gastrula-halves grafted together, the epidermis of each of which is thrown into ridges and folds in vainly trying to overgrow the other. b. The same, 16 hours later, showing intensification of ridges and folds. (From Spemann, Arch. Entzvmech. cxxiii, 1931.) diameter. Thirdly, the cells just beneath the marginal zone in the dorsal meridian have the tendency to invaginate and form a pit-like depression. Normally, of course, all these processes take place together, with the result that the excess of material obtained by the stretching of the marginal zone becomes tucked into the invagina- tion round the rim of what may now be called the blastopore. New material, as it arrives at the rim, becomes tucked in, and this tendency to roll or tuck in is also an independent process. Mean- while, the space vacated on the surface by the material which has thus been invaginated, is occupied by the shifting and expanding regions of the animal 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
