Figure 2 in Revising the definition of the crustacean seta and setal classification systems based on examinations of the mouthpart setae of seven species of decapods

Figure 2. Types of projections found on the general cuticle. A, type I projection, a seta, is an elongate circular projection, which is articulated with the general cuticle (arrow). It is the most common type of projection. B, type II projection, a seta, from maxilla 1 of Pagurus bernhardus with a more or less direct transition into the general cuticle. In the other species articulated setae are situated in the same place (compare with Fig. 11A). They may have small outgrowths (arrows). C, type III projections, denticles, from maxilliped 1 of Panulirus argus. Arrows indicate direct transition into general cuticle without an articulation. D, type IV projections, setules, from the paragnath of Stenopus hispidus. Arrows indicate serration and arrowheads indicate articulation with the general cuticle. Note the flattened shape at the base.