摘要：

To determine the regulative ability of Lymnaea eggs one or more cells were deleted by puncturing or shaking eggs at the 2, 4, 8 and 16-cell stages. Normal snails developed from: one/two, three/four, and two/four embryos; from 8-cell embryos in which one, two, or three cells of the first quartet of micromeres or one or two macromeres were deleted; and from 16-cell stage embryos in which one cell of the second quartet of micromeres or one macromere was deleted. Only one/two embryos that cleaved as though they were whole eggs up to the 24-cell stage developed normally. Normal development of other partial embryos was associated with partial cleavage. Developmental abnormalities of partial embryos included death in the cleavage period; arrested gastrulae; trochophores, or veligers; and abnormal snails with head malformations, everted stomodea, or conical shells.

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