FIGURE 4 in A review of the Polystira clade—the Neotropic's largest marine gastropod radiation (Neogastropoda: Conoidea: Turridae sensu stricto)

FIGURE 4. Outer lip and anal sinus morphology in adult shells of six extant Polystira species. Note variability in depth and shape of anal sinus, and of the shapes of the upper (posterior) and lower (anterior) limbs of the outer lip. Not to scale.