. The elements of experimental embryology. Embryology, Experimental; Embryology. a b Fig. 54 Organ-forming substances in Dentalium. a, Normal larva, 24 hours old. b, Larva lacking apical organ and post-trochal region, obtained after removal of the first polar lobe. (From Jenkinson, Experimental Embryology, Oxford, 1909, after Wilson.) AB, A,B,ov C blastomeres) lacks the apical organ and post-trochal region. If the polar lobe is cut off at the onset of the second cleavage, the larva possesses the apical organ and lacks the post-trochal region. At the approach of the second cleavage, therefore,
. The elements of experimental embryology. Embryology, Experimental; Embryology. a b Fig. 54 Organ-forming substances in Dentalium. a, Normal larva, 24 hours old. b, Larva lacking apical organ and post-trochal region, obtained after removal of the first polar lobe. (From Jenkinson, Experimental Embryology, Oxford, 1909, after Wilson.) AB, A,B,ov C blastomeres) lacks the apical organ and post-trochal region. If the polar lobe is cut off at the onset of the second cleavage, the larva possesses the apical organ and lacks the post-trochal region. At the approach of the second cleavage, therefore, the organ-form- ing materials for the post-trochal region become separated from those for the apical organ, for the latter are not included in the polar lobe at its second extrusion; instead, they presumably migrate into the animal end of the D blastomere where they are in a position to become included in i ^ at the next cleavage (fig. 54). Similar occurrences whereby chemo-differentiated substances present in the uncleaved egg are restricted by specialisations of the. 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
