Dactylus

The dactylus is the tip region of the tentacular club of cephalopods and of the leg of some crustaceans (see arthropod leg). In cephalopods, the dactylus is narrow and often characterized by the asymmetrical placement of suckers (i.e., the ventral expansion of the club) and the absence of a dorsal protective membrane. In crustaceans, the dactylus is the seventh and terminal segment of their thoracic appendages. In certain instances the dactylus, together with the propodus, form the claw.

The term dactylus means "finger" in Greek.

References

Cephalopod anatomy Shell Shell types External shells: Ammonoid shell Argonautid eggcase Nautiloid shell Orthocone Internal shells: Belemnoid guard Cirrate shell Cuttlebone Gladius (pen) Spirula shell Stylet External features Aperture Apex Callus Lirae Periostracum Sculpture Spire Sutures Umbilicus Internal features Body chamber Camerae Nacre Phragmocone Septa Siphuncle Whorls Mantle External anatomy Funnel Dermal structures Fins (wings) Mantle locking-apparatus Internal anatomy Branchial hearts Ctenidia (gills) Hepatopancreas (digestive gland) Ink sac and ink Needham's sac Nephridia ("kidneys") Nidamental glands Osphradium Pericardial glands Head and limbs Brachial crown Arms Hectocotylus Tentacles Buccal region Aptychus Beak Odontophore Radula Spadix and antispadix Other parts Eyes Statocysts General Chromatophores Photophores Nervous system Squid giant axon Squid giant synapse Developmental stages: Spawn → Paralarva (Doratopsis stage) → Juvenile → Subadult → Adult • Protoconch (embryonic shell)