C. elegans cell lineage

Exactly 1033 somatic cells on male, 959 on hermaphrodite, every time, counted as of 2020. A beauty.

Exactly 131 commit apoptosis in the hermaphrodite.

www.wormatlas.org/celllineages.html contains the full lineage as some huge and impossible to view images. This image was taken directly from The embryonic cell lineage of the nematode Caenorhabditis elegans where it is split across many pages, it is a thing of beauty on the PDF.

www.wormatlas.org/celllistsulston.htm contains a non-hierarchical table with the cells and their names.