• (n.) One of the cells which, in the Coelenterata, develop into cnidae.
(from the article `nematocyst`) ...capsule that is found chiefly in members of the phylum Cnidaria (e.g., jellyfish, corals, sea anemones). The capsule, which occurs on the body ...
Developing form of cnidocyte. ... (18 Nov 1997) ... 
Cni'do·blast noun [ Cnida + -blast .] (Zoology) One of the cells which, in the Cœlenterata, develop into cnidæ. 
the cell within which a nematocyst is developed.