Amebocyte

An amebocyte or amoebocyte (/əˈmiː.bə.saɪt/) is a motile cell (moving like an amoeba) in the bodies of invertebrates including cnidaria, echinoderms, molluscs, tunicates, sponges, and some chelicerates.

Moving by pseudopodia, amebocytes can manifest as blood cells or play a similar biological role.

Depending on the species, an amebocyte may also digest and distribute food, dispose of wastes, form skeletal fibers, fight infections, and change into other cell types.

[2][permanent dead link‍][3][permanent dead link‍] In tunicates they are blood cells and use pseudopodia to attack pathogens that enter the blood, transport nutrients, get rid of waste products, and grow/repair the tunica.

[4] The amebocytes of Limulus are characterized by large granules around the nucleus, ribosome-like particles in the cytoplasm, and a circumferential ring of microtubules, which likely help maintain the cells' prolate-to-fusiform shape.