BIGELOW. — Development of Lepas. 
PLATE 5. 
Figures from transparent preparations of entire eggs. Vegetative pole at the 
left in figures which represent lateral views. 
Fig. 39. 
Fig. 40. 
Fig. 41. 
Fig. 42. 
Fig. 48. 
Fig. 44. 
Fig. 45. 
. Fig. 46. 
Eight-cell stage from animal pole. The seven “ protoplasmic ” cells are 
in the fourth cleavage; the nucleus of yolk-cell (d*!) is preparing for 
division. 
Same egg in lateral view. Yolk at vegetative pole of cell d*1. 
Fifteen “protoplasmic” cells; the yolk-cell (d41, mes-entoblast) divid- 
ing. Lateral view. 
Sixteen-cell stage from animal pole. Nuclei of all cells are in “resting ” 
phase. Primary mesoblast (d*?) separated from entoblast (d*1). 
Same egg viewed from vegetative pole. Oil spherules near lower surface 
of the yolk-cell. 
Sixteen-cell stage from animal pole. All cells, except yolk-cell (entoblast 
d>-1) and the primary mesoblast cell (d*?), are undergoing the fifth 
cleavage. 
Same egg in lateral view. 
Same stage from vegetative pole. The three mes-ectoblasts (compare 
Fig. 43, a®-2, 65-2, c52) contiguous to yolk-cell. 
Nore. — Cell a5? is represented as divided, and its derivatives should have been 
labelled a®3, a6-4, ; 
