Simon (Peter) – Keys represent Peter as holder of the keys to the Kingdom of Heaven.
Andrew – (two symbols) An X-shaped cross is still called St. Andrews cross and is one of his Apostolic symbols. The other is two crossed fish because he was formerly a fisherman and was first Apostle active in bringing others to Jesus.
James (son of Zebedee) – His symbol is three shells, the sign of his pilgrimage by the sea.
John (known as Beloved Disciple) – It is said that an attempt was made on his life by giving him a chalice of poison from which God spared him. A chalice with a snake in it is his symbol.
Philip – His symbol is a basket, because of his part in the feeding of the five thousand.
Bartholomew (Nathanael) – He died as a martyr for his Lord. He was flayed alive with knives. His Apostolic symbol is three parallel knives.
Thomas (Didymas) – In India he suffered martyrdom and was killed by a lance. His symbol is a group of spears, stones, and arrows.
Matthew (Levi) – His symbol is three money bags reminding us he was a tax collector before Jesus called him.
James (son of Alphaeus) – He died as a martyr and his body was sawed in pieces. The saw is his Apostolic symbol.
Jude (Thaddaeus) – The chosen symbol for him was a ship because he was a missionary thought to be a fisherman.
Simon (The Zealot) – His symbol is a fish lying on a Bible, indicating he was a former fisherman who became a fisher of men.
Judas Iscariot – Betrayer of Jesus Christ – no symbol.
Mattias – Chosen by remaining eleven Apostles in order to have twelve again.
Information from NAS Bible, Special Study Aids, by Thomas Nelson, 1978, 1979.