. Journal of morphology. Pigs. 4, 5 Eight-cell stage of eggs of C. plana and C. convexa, drawn to the samescale, showing relative sizes of blastomeres, nuclei, spindles, etc. Figs. 6, 7 Twenty-four-cell stage of eggs of C. plana and C. convexa, drawn tosame scale and showing relative sizes of blastomeres, nuclei, and protoplasmic anddcutoplasmic regions of the egg. 174 EDWIN G. CONKLIN large macromeres which contain httle cytoplasm and almost allthe yolk. The early subdivisions of the ectomeres take place inexactly the same way in the largest as in the smallest eggs,though the individual cells
. Journal of morphology. Pigs. 4, 5 Eight-cell stage of eggs of C. plana and C. convexa, drawn to the samescale, showing relative sizes of blastomeres, nuclei, spindles, etc. Figs. 6, 7 Twenty-four-cell stage of eggs of C. plana and C. convexa, drawn tosame scale and showing relative sizes of blastomeres, nuclei, and protoplasmic anddcutoplasmic regions of the egg. 174 EDWIN G. CONKLIN large macromeres which contain httle cytoplasm and almost allthe yolk. The early subdivisions of the ectomeres take place inexactly the same way in the largest as in the smallest eggs,though the individual cells are larger in the former than in thelatter. When the third and last quartet of ectomeres is separatedfrom the macromeres, the first quartet has divided, and, in thesmaller eggs of C. plana, the second quartet also, so that thecompletely segregated ectoderm consists of a plate of sixteen, ortwenty, protoplasmic cells resting upon the great yolk cells, ormacromeres (figs. 6, 7). Since this ectodermal plate containsmost of
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Keywords: ., bookcentury1900, bookdecade1, booksubjectphysiology, bookyear1912
