dactylus

noun

1. Synonym of dactyl (“type of metrical foot”).
2. The tip of a cephalopod's tentacle club

   “The distal end of the club, the dactylus (finger), is pointed and attenuated but is covered with hundreds of small suckers.”

   “[…] suckers of carpus and dactylus portions small […]”

3. The tip of a crustacean's leg

   “The tip of the dactylus is short and hooked, with a scoop-shaped depression on the anterior surface.”

   “Pereiopod 1 […] dactylus with 3 pointed processes on posterior margin (Fig. 2g).”