1. Despite their rich fossil record with thousands of described hypostome . 2. Many variations in shape and placement of the hypostome have been described. 3. Partly because of this, and partly because of their rather indistinct hypostome . 4. Variation in trilobite hypostome morphology is crucial in modern discussions of trilobite phylogeny. 5. It includes three hypostome that creates an indention superior to the gastric cavity. 6. The hypostome , a small rigid plate comparable to the ventral plate in other arthropods. 7. The " hypostome " is inserted and this provides the initial attachment strength. 8. Functional interpretations of hypostome shape also allow for reasonable speculation on the feeding habits of trilobite species. 9. Of particular interest are " macula ", the small areas of thinned cuticle on the underside of the hypostome . 10. A toothless mouth and stomach sat upon the hypostome with the mouth facing backward at the rear edge of the hypostome.
