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

v t e 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 Dermal structures Fins (wings) Flotation devices ("secondary fins") Mantle locking-apparatus Tail Internal anatomy Branchial hearts Ctenidia (gills) Hepatopancreas (digestive gland) Ink sac and ink Needham's sac Nephridia ("kidneys") Nidamental glands Osphradium Pericardial glands Funnel Foveola Funnel groove Funnel locking-apparatus Funnel organ Funnel retractor muscles Funnel valve Head and limbs Brachial crown Arms Hectocotylus Tentacles Carpus Dactylus Manus Suckers and hooks Buccal region Aptychus Beak Odontophore Radula Occipital region Occipital crest Occipital folds (nuchal folds) Occipital membrane Olfactory organ Nuchal organ Other parts Eyes Cornea Eye pore Eyelid sinus Secondary eyelid Statocysts General Chromatophores Photophores Nervous system Squid giant axon Squid giant synapse Developmental stages: Spawn → Paralarva (Doratopsis stage) → Juvenile → Subadult → Adult • Protoconch (embryonic shell)