EMBRYOLOGY OF CRYPTOBRANCHUS 



135 



z.p. 



36 



37 





mWdiVMm 



:0°o'Cn. 



w^ 





■ O:. 



--Q.sOic'o 



38 



39 



40 



Figs. 36 to 40 Meridional sections showing the second polar spindle, and the for- 

 mation of the second polar body and the egg-nucleus in Cryptobranchus allegheni- 

 ensis. X 340. 



Fig. 36 Section through the second polar spindle of an unfertilized egg taken 

 from the uterus of a ripe female, z. p., zona pellucida; p. b. I, debris of the degen- 

 erating first polar body. 



Fig. 37 Section through the second polar spindle of an egg killed 15 minutes 

 after fertilization. The section lies in the plane of the equator of the spindle. 



Fig. 38 Late anaphase of the second polar spindle in an egg killed 2^ hours after 

 fertilization. A considerable part of the chromatin is left in an adjacent 

 section. 



Figs. 39 and 40 Two consecutive sections through an egg killed 5 hours after 

 fertilization ; the first figure shows the second polar body, the second figure shows in 

 addition the newly-formed egg-nucleus. 



