Summary of the development of the leech Helobdella robusta. At first cleavage, the larger, CD cell, inherits both caps of teloplasm. In the next cleavage, the D blastomere retains both teloplasmic caps, and the vegetal teloplasm begins migrating towards the animal teloplasm. The two plasms will merge at the animal pole. The 8-cell embryo.
Third cleavage produces a set of very small micromeres and a ste of large vegetal macromeres.
The D' cell contains all the teloplasm near its animal cap. The 12-cell embryo. Each of these cells contains some teloplasm. The teloblasts produce bandlets of cells. Lower case letters indicate bandlet identities.