TIME RELATIONS OF PARTURITION, MATURATION, ETC. 1 7 



first spindle may arise as late as about 28 hours p.p. According to these 

 observations, then, the first spindle divides and gives rise to the first 

 polar cell not earlier than 13! hours p.p., nor later than 28^ hours p.p. 

 This conclusion is rendered the more probable by the observations that 



the youngest egg in which the first polar cell was completely cut off 

 was taken from a female killed 14 hours p.p., and that the oldest egg in 

 which the formation of the first polar cell was barely completed was from 

 an individual killed 27 hours p.p. 



Very frequently the second spindle has been found completely 

 formed as early as 16 hours, and occasionally as early as 14^, p.p. The 



