Complex sentence: The librarians added "Readmore Books" to his full name, inspired partially by the cartoon library cat Cap'n O. G. Readmore, although he was usually referred to as just "Dewey".
Split into simpler sentences: The librarians added "Readmore Books" to make a full name, inspired partially by the cartoon library cat Cap'n O. G. Readmore. The cat was usually referred to as just "Dewey".