Sorry. Think of them as wart like structures that the anemone can use to adhere to substrate. From the link I provided: "Most host actinians have, in the upper part, longitudinal rows of small warts (verrucae; singular is verruca) to which particles of gravel may adhere; commonly these are pigmented differently from the rest of the column."
Here is a picture showing the verrucae of one of my carpets (
Stichodactyla gigantea):
Offhand I do not have pictures of the verrucae of
H. magnifica versus
E. quadricolor, sorry, although a quick google search should yield plenty of results.