Embryology of insects and myriapods; Embryology of insects and myriapods; the developmental history of insects, centipedes, and millepedes from egg desposition [!] to hatching embryologyofinse00joha Year: 1941 if-emb Fig. 338.—Scolopendra cingulata. (emb) Embryonic rudiment, (cp) Cumulus primitivus (early rudiment), {yp) Yolk pyramid (macromere). (Adapted from Heymons.) Germ Layers.—The germ disk by rapid mitotic division soon becomes several layers thick (Fig. 339), in structure resembling the cumulus primitivus in spiders, the yolk masses immediately below being broken up. A few cells set f
Embryology of insects and myriapods; Embryology of insects and myriapods; the developmental history of insects, centipedes, and millepedes from egg desposition [!] to hatching embryologyofinse00joha Year: 1941 if-emb Fig. 338.—Scolopendra cingulata. (emb) Embryonic rudiment, (cp) Cumulus primitivus (early rudiment), {yp) Yolk pyramid (macromere). (Adapted from Heymons.) Germ Layers.—The germ disk by rapid mitotic division soon becomes several layers thick (Fig. 339), in structure resembling the cumulus primitivus in spiders, the yolk masses immediately below being broken up. A few cells set free from the inner surface wander into the yolk, forming yolk cells, which are found not only on the dividing surfaces of Fig. 339.—Scolopendra cingulata. Section through early rudiment, (blast) Blastoderm. (cp) Cumulus primitivus (early rudiment). (ent) Entoderm cell. (Adapted from Heymons.) the yolk pyramids but also in the peripheral part of the pyramids. A few degenerating cells, the paracytes, may also be observed. Later yolk cells are also gradually given off from the inner surface of the blastoderm. The formation of the entoderm takes place in the same manner as that of the yolk cells. Cells are set free frorh numerous points of the inner
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