It is a sclerotised ring, composed of two lateral crescents, that surrounds the anal opening. Typically, it has numerous wax-exuding pores (which may be in one or more rows) and 3, 4, or more pairs of long setae, the anal ring setae. The anal ring is at the inner end of the anal tube; when withdrawn and inverted, this tube lies within the body cavity and usually extends well anterior to the anal plates.