Archaeocyte

Archaeocytes or ameobocytes (from Greek archaios "beginning" and kytos "hollow vessel") are amoeboid cells found in sponges. They are totipotent and have varied functions depending on the species.

Location
Archaeocytes are located in the mesohyl, an acellular gelatinous matrix, along with other specialized sponge cells including collencytes and structural elements called spicules. They move about within the mesohyl with ameoba-like movements performing a number of important functions.

Functions
Cellular differentiation is an essential function of the archaeocyte. All specialized cells within the sponge have its origins with the archaeocyte. This is especially important in reproduction as the sex cells of the sponge in sexual reproduction are formed from these amoeboid cells. Similarly in asexual reproduction amoebocytes result in the formation of gemmules which are cyst-like spheres containing more amoebocytes as well as other sponge cells including the phylum specific choanocyte.