РгАТЕ ІП. 
Living Eggs of Cynthia partita; First to Fourth Cleavage. 
Figs. 25 and 26-—Same egg as the one shown in figs. 21-24; final stages in the first cleavage. 
Fig. 27.—Another egg at the close of the first cleavage ; seen from the posterior pole. 
Fig. 28.—End view of egg of same stage as preceding, showing the lateral limits of the yellow cres- 
cent, the clear protoplasm in the upper hemisphere and the yolk in the lower. The 
' anterior portion of the lower hemisphere is composed of light gray material ; i is the 
ray crescent and gives rise to chorda and neural plate. 
Fig. 29.—Four-cell stage, viewed from the animal pole. 
Fig. 30. —Similar egg seen from the vegetal pole; the crescent covers about half of the posterior 
blastomeres, 
Fig. 31.—Eight-cell stage; the crescent is limited entirely to the two posterior blastomeres at the vege- 
tal pole; wi under observation the furrow between B** and b** shifted from the posi- 
tion indieated by the faint line to that shown by the heavy line, thus giving rise to the 
“cross furrow” shown in the next figure. 
Fig. 32.—Eight-cell stage, viewed from the right side, showing a small amount of yellow protoplasm 
around all the nuclei. 
Fig. 33.—Same stage viewed from the vegetal pole, showing bi yolk laden endoderm cells and the 
crescent, 
Fig. 34.—Same stage viewed from the posterior-animal pole, showing the clear ectodermal cells and 
the crescent. 
Fig. 35.—Same stage seen from the anterior-vegetal pole; yellow protoplasm around all the nuclei. 
Fig. 36.—Fourth cleavage of the egg seen reo the vegetal pole. 
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