- capitulum
- carapace
- carapace glands
- carnivorousness
- carotenoid
- caudal furca
- caudal process
- central nervous system
- cerebrum
- Cetacea
- character
- chelate
- chemistry
- chitin
- circum-oesophageal ganglion
- class
- cleaning leg
- commensalism
- competition
- compound eyes
- concave
- conspecific
- continental slope
- convergence
- convex
- copulatory appendage
- coxa
- coxale
- Crustacea
- cuticle