Note nodule-like projections above some of the cells; these are stinging cells, or cnidoblasts.
Observe the cnidoblasts of the tentacles and note that many of them have thrown out long whip-like processes (fig. 7, C).
The cnidoblasts are the mother-cells of the nematocysts, each cell producing one nematocyst in its interior.
Packed in among these are gland cells, sense cells, and cnidoblasts.