Asnail shell is quite different from the familiar bony skeleton of a mammal. in what ways does a shell function as a skeleton? peer review

The shell provides a rigid structure to attach muscles to and supports soft body parts. That is what a skeleton does. A shell is basically an exoskeleton. Exoskeletons contain rigid components that have a set of functional roles including protection, excretion, sensing, support, feeding and acting as a barrier against harmful predators.