Division of Lesquereusia spiralis
The next photomicrographs show the division of a specimen of Lesquereusia spiralis. I found this cell when the building of the new shell, the daughter cell, had already started and was, I guess, about ten minutes on its way.
In the period before this division, the mother cell has collected a lot of building material in its cytoplasm. Many shelled amoebae collect this material from their environment, but others, like Lesquereusia spiralis, secrete these elements in their cytoplasm. My observation started when the cell was pushing its elements outwards. This process can be compared with blowing up a balloon, where the elements move to the outside.
00.06 h.: The amoeba continues to expand.
00.12 h.: Vacuoles are visible in the new shell. They serve as a kind of template to shape the new shell.
00.17 h.: The new shell reaches its definite shape.
00.30 h.: Vacuoles are clearly visible in the daughter shell.
00.42 h.: The cytoplasm moves back into the mother shell, the vacuoles disappear.
00.52 h.: In the mean time, the nucleus has divided and one of the nuclei moved into the new shell. During and after the division of the nucleus, a part of the cytoplasma moves back and forth between both shells in a turbulent stream for about ten minutes.
01.07 h.: The cytoplasma separates. The new cell is finished. The total process of division lasted for about 75 minutes.