BIGELOW. - Development of Lepas. 



PLATE 11. 



Lepas fascicularis. 



The figures in parenthesis following the descriptions refer to corresponding 

 stages of L. anatifera. 



Fig. 95-97. Outlines of a living egg, showing its rotation within the vitelline 



membrane during the first cleavage. (Figs. 6-16.) 

 Figs. 98-110. Drawn from transparent preparations of entire eggs. 

 Fig. 98. First cleavage, spindle arranged transversely to chief axis of egg. (Figs. 



21-23.) 



Fig. 99. Second cleavage. View from animal pole. (Fig. 31.) 

 Figs. 100, 101. Four-cell stage from animal pole. (Figs. 32, 34.) 

 Fig. 102. Same from vegetative pole. (Fig. 35.) 

 Fig. 103. Same seen from the left side. " Protoplasmic " cells already in third 



cleavage. (Fig. 36.) 

 Tig. 104. Eight cells. View from animal pole. Seven "protoplasmic" cells in 



fourth cleavage. Yolk-cell (rf 4 ' 1 ) retarded in division. (Fig. 39.) 

 Fig. 105. Same stage from left side. (Fig. 40.) 

 Fig. 106. Same stage viewed from vegetative pole. 

 Fig. 107. The divisions shown in Figure 104 as beginning are now completed. 



View from animal pole. (Compare with Figs. 41, 42.) 

 Fig. 108. Same stage viewed from left side. Yolk-cell (o? 4>1 mes-entoblast) in 



fourth cleavage. (Fig. 41.) 

 Fig 109. Optical sagittal section of egg in same stage viewed from left side. 



(Fig. 67.) 

 Fig. 110. Optical sagittal section of sixteen-cell stage. Left lateral view. (Fig. 



68) 



