How is the mollusk mantle related to its shell?
Mantle or Palladium only secretes shell. It's an adaptation for protection .
Shell here works as exoskeleton & is calcareous by nature.
Calcareous suggests partly or completely composed of calcium carbonate .
All Mollusks have this exoskeleton.
- Most of the members of Cephalopods do not have shells (as they respire through general body surface)
- The shell of the Sepia (Cuttle fish) is not well-formed