BigELow. — Development of Lepas. 
PLATE 9. 
Figures from three sets of consecutive serial sections. Vegetative (ventral) pole 
and blastopore are at the /eft in Figures 74-80 and at the /ower side in Figures 
81-86. Blastoderm one cell in thickness. 
Figs. 74-77. Series of consecutive sections parallel to sagittal plane from an egg 
in sixty-two-cell stage, counting two dividing primary mesoblasts 
as four cells. The first and sixth sections of this series contained 
only blastoderm cells and have not been figured. 
Figs. 78-80. Series of consecutive sections parallel to sagittal plane through egg 
in a stage with about one hundred and twenty cells. The first and 
last sections of the series are not figured. 
Figs. 81-86. Series of consecutive transverse sections (viewed from their posterior 
faces) from an egg in same stage as that of last series. Figure 81 
shows the most posterior of the sections represented. The first and 
last sections of the series, containing only blastoderm cells, and 
three anterior to and similar to Figure 86 have not been figured. 
