626 WILSON. 



PLATE XXXII. 

 [All from preparations ; 270 diameters.] 



Fig. 37. 32-celled stage, bilateral form /, lower pole. 



Fig. 38. The same specimen from the side. 



Fig. 39. 32-celled stage, strict bilateral form /, from one end. [Compare 

 Hatschek, Taf. I, Fig. 10.] 



Fig. 40. 32-celled stage, slightly modified radial form, lower pole. 



Fig. 41. Sixth cleavage, bilateral form /, viewed obliquely from below. Origin 

 of third group of micromeres. 



Fig. 42. The same specimen from the side. Note complete irregularity of the 

 cleavage-planes in the micromeres. 



Fig. 43. 64-celled stage, from the side. 



Fig. 44. The same specimen from lower pole. Slightly modified bilateral 

 form /. 



Fig. 45. 128-celled stage, bilateral form /, from lower pole, showing fourth 

 group of micromeres. 



Fig. 46. 256-celled stage, from lower pole, mixed form. Designations of the 

 macromeres arbitrary. 



Fig. 47. Seventh cleavage, bilateral form /, from the side, showing origin of 

 fourth group of micromeres. 



