Fig. 2. Ultrastructural images of a multipolar spindle in a polyspermic zygote of S. lomentaria. Three sections are shown from the consecutive serial sections of the same cell. The cell is at the same point in mitosis as shown in Fig. 1H. Arrows show centrioles. (A) One pole of the tripolar spindle. Spindle MTs from around the centriole (arrow), elongate towards the chromosomes and become arranged at equators of the multipolar spindle. The nuclear envelope is almost intact, except at the spindle poles. (B) Another spindle pole (arrow). Golgi bodies (G) exit at nearby centrioles. (C) One centrosome is located away from the spindle. The Golgi body is close to the centrosome. The bottom arrow shows the same mitotic pole as in B.