Exoskeletons are derived from the epidermis and is composed of chitin in arthropods (insects, spiders, ticks, shrimps, crabs, lobsters).
ˈɛksoʊskˌɛlᵻtənz ɑːɹ dᵻɹˈaɪvd fɹʌmðɪ ˌɛpɪdˈɜːmɪs ænd ɪz kəmpˈoʊzd ʌv tʃˈɪtɪn ɪn ˈɑːɹθɹəpˌɑːdz ˈɪnsɛkts, spˈaɪdɚz, tˈɪks, ʃɹˈɪmps, kɹˈæbz, lˈɑːbstɚz.