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• Freshwater and Marine Image Bank

[Quahog Eggs]:
Fig.1.--Mature egg ready for union with male cell.
Fig.2.--Spermatozoa (male cells). Note length of tail and shape of head. No attempts were made to study the minute anatomy.
Fig.3.--Egg, twenty-five minutes after fecundation, showing the two polar cells (pc) and the faintly developed yolk love.
Fig.4.--Egg just previous to the first cleavage, showing large yolk lobe.
Fig.5.--The two-celled stage at the completion of the first cleavage, fifty minutes after fecundation. The larger cell contains the yolk lobe.
Figs. 6,7,8,9.--This series illustrates the process of cleavage in the egg during the change from the two-celled to the four-celled stage.
Fig.10.--The four-celled stage, one hundred and ten munites after fecundation. Side view.
Figs. 11,12.--The eight-celled stage, one hundred and forty-five minutes after fecundation.
Fig.13.--The sixteen-celled stae, one hundred and eighty-five munites after fecundation. Side view.
Fig.14.--The thirty-