"1, Portion of epithelium from the tentacle of an Actinian, showing three supporting cells and one sense cell; 2, a cnidoblast with enclosed nematocyst from the same specimen; 3 and 4, two forms of gland cell from the stomodaeum; 5a, 5b, epithelio-muscular cells from the tentacle in different states of contraction; 5c, an epithelio-muscular cell from the endoderm, containing a symbiotic zooxanthella ; 6, a ganglion cell fro mthe ectoderm of the peristome." —Encyclopedia Britannica, 1910

Tentacles

"1, Portion of epithelium from the tentacle of an Actinian, showing three supporting cells and one sense…