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 318 EMBRYOLOGY OF INSECTS AND MYRIAPODS The second polar body (Bl) and the inner nucleus (A2) of the first polar body now fuse to form the polar nucleus, or the so-called 'paranucleus' (Fig. 267,7iu. p), the outer nucleus (Al) of the first polar body later under- going dissolution. That only two and not all three polar bodies enter into the formation of the polar nucleus (paranucleus) i
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 318 EMBRYOLOGY OF INSECTS AND MYRIAPODS The second polar body (Bl) and the inner nucleus (A2) of the first polar body now fuse to form the polar nucleus, or the so-called 'paranucleus' (Fig. 267,7iu. p), the outer nucleus (Al) of the first polar body later under- going dissolution. That only two and not all three polar bodies enter into the formation of the polar nucleus (paranucleus) is proved by the fact amt Fig. 272. Fig. 273. Fig. 270.—Litomastix. Eight-cell stage, {amt) Trophamnion. {his) Embryonic blastomere. {his. os) Blastomere with oosome. (nw. p) Polar nuclei. Fig. 271.—Litomastix. 14-cell stage, {amt) Trophamnion. {his) Blastomere. {his. os) Blastomere with oosome. {nup) Polar nuclei. Fig. 272.—Litomastix. 60-cell stage, {amt) Trophamnion, or polar membrane, {nup) Polar nuclei. Fig. 273.—Litomastix. 221-cell morula, {amt) Trophamnion. (c) Embryonic cells. {csp) Spindle cells, {myc) Mesenchyme cells of host. that the diploid number of 16 chromosomes and not the triploid number is present. The egg is inseminated by a single sperm, which after having entered the egg loses its tail, only the head being transformed into the male pronucleus (Fig. 267, sp). During the fusion of the male and female pronuclei the oosome moves from its original more or less central position
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