hypostome

noun4

1. •
   Any of certain mouth appendages of some insects, arachnids, crustaceans, and hydrozoa.

   • Figure 7.4 Argas persicus^([fowl tick])[…](b) Hypostome of larval stage. The toothed hypostome is easily visible in the larval stage. — 2022
2. •
   The ventral mouthpart plate in trilobites;
3. •
   The barbed attachment structure associated with the mouthparts of parasitic arachnids (e.g. ticks);
4. •
   The oral tip surrounded by tentacles in hydrozoan cnidarians.