Plate IV. 



58. Central aster of the first maturation figure, showiug archiplasmic 

 differentiation of the rays. X 2000. 



59. Sperm-aster in tlie nuclear area. In the next section is found the 

 first maturation figure. X 860. 



60. Kays of the maturation aster reaching chromatin masses, x ^^^^^'*- 



01. JNlitotic figure in an ether egg of Asterias, in which, one of the asters 

 has divided into two. X 526. 



62. Sperm-asters approaching the first maturation figure. Some of the 

 chromosomes are attracted towards the sperm asters. X 806. 



63. Two cytasters in an ether egg of Asterias. X 1566. 



64. Two asters in an enucleated blastomere of an ether egg of Asterias. 

 X 1566. 



05. Two asters connected by a spindle in an enucleated blastomere of 

 an ether egg of Asterias. X 860. 



06. Spindle formed between the cenlral aster of the first maturation 

 figure and the sperm-aster, x 800. 



07. Spindle formed between two sperm-asters in a dispermic egg. X 800. 



08. Sperm-nucleus approaching the egg-nucleus. The sperm-asters are 

 behind the sperm-nucleus. One of the centrioles is under the nucleus. 

 Fountain figure in the sperm-rays. Combination of four sections. X 800. 



09. Crossing of rays between the sperm and egg-asters. Accumulation 

 of the nuclear fluid between the asters. X 800. 



70. First polocyte produced by KCl -f CaCL (unfertilized egg). X 866. 



72. Five polocytes produced by KCl -f CaClj (unfertilized egg). X 806. 



