What purpose does a chitinous cuticle serve in an earthworm?

The purpose of chitinous cuticle serve in an earthworm is to prevent the worm from dehydration  and also provides protection. Cuticle is a thin, non-cellular coating on the surface that prevents dehydration and provides protection. The cuticle also allow oxygen to pass into the coelomic fluid and blood of the worm. It protects the worm from drying out and also protects the epidermis from abrasion from soil particles. 

C. osmosis.

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