Kofoid. — Development of Limax. 



PLATE I. 



Figures 1 to 7 drawn from the same living egg. X 275. 



Fig. 1. Two-cell stage, beginning of flattened condition, 11.52 a. m. 



Fig. 2. Same egg at 12.45 p. m. First trace of cleavage cavity. 



Fig. 3. Same egg at 12.50 p. m. 



Fig. 4. Same egg at 1.01 p. m. 



Fig. 5. Same egg at 1.20 p. M. Maximum size of cleavage cavity. 



Fig. 6. First (partial) expulsion of contents of cleavage cavity. 1.30 p. m. 



Fig. 7. Same egg at 1.55 p. m. Spindles of the third generation present; the 

 asters of the near ends of the spindles in focus. 



» 

 Figures 8 to 13 drawn from another living egg of the same laying as 

 Figures 1 to 7. X 275. 



Fig. 8. At 3.45 p. m. Division into four cells completed. Typical alternate 

 arrangement of the four blastomeres. Viewed in the direction of the 

 second plane of cleavage, therefore perpendicular to the direction of 

 Figures 1 to 7. 



Same egg at 3.55 p. m. Formation of a cleavage cavity. 



Same egg at 4.05 p. m. 



Maximum development of the cleavage cavity. 4.35 p. m. 



Same egg after a gradual total expulsion of the contents of the cavity. 

 4.45 p. m. Spindles of the fourth generation present. 



Formation of the eight cells of the fourth generation. Persistence of the 

 cleavage cavity. 5.45 p. m. 



Lateral view of two-cell stage. First cleavage plane just completed. 

 Astrocoels present. X 490. 



