. The elements of experimental embryology. Embryology, Experimental; Embryology. THE FUNCTIONAL PERIOD OF DEVELOPMENT 429 An interesting half-way stage between chemical eflFects due to contact, as in the determination of a lens by the eye-cup, and those due to circulatory hormones, is seen in the perforation of the right- hand side of the operculum in Anuran tadpoles during meta- morphosis. As is well known, the rudiments of the fore-limbs develop beneath the operculum, and while the left fore-limb makes its way out through the open spiracle, the right protrudes through a special perforation.

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. The elements of experimental embryology. Embryology, Experimental; Embryology. THE FUNCTIONAL PERIOD OF DEVELOPMENT 429 An interesting half-way stage between chemical eflFects due to contact, as in the determination of a lens by the eye-cup, and those due to circulatory hormones, is seen in the perforation of the right- hand side of the operculum in Anuran tadpoles during meta- morphosis. As is well known, the rudiments of the fore-limbs develop beneath the operculum, and while the left fore-limb makes its way out through the open spiracle, the right protrudes through a special perforation. After extirpation of the right fore-limb rudi-. m V'— 1^'-^- '^ '':i. W^ OG. 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