Pinacocyte

Minchin (1896, 1898, 1908) also concluded that the pinacocytes could leave the dermal epithelium and become calcoblasts in both larva and adult sponge.

As you can see in Fig 27.7, sponges have only three types of cells in their bodies: pinacocytes (epithelial cells), choanocytes (collar cells) and amoebocytes (amoeboid cells).

Despite this, in some studies the origin of new pinacocytes is not clear or is disputed (Wilson and Penney, 1930; Borojevic and Lévi, 1965).