A rare species of marine crabs with a clear cross-shaped mark on their shells is found in Malaysian and Indonesian waters. Its scientific name is 'Crucifix crab' or Charybdis feriatus. Rare specimens of the species have been collected from other places like Goa in India. There is a popular belief about the origin of the cross mark on the shells of these crabs.
In 1546, St. Francis Xavier, after strenuous and successful missionary activities in India, set out to the lands and islands to the east of India such as Singapore, Philippines, Malacca and Indonesia. In February 1546, the boat in which the saint sailed was caught in a storm in Eastern Indonesia. In an attempt to calm the tempest, he leaned out of the boat and dipped his crucifix in the raging waves prayerfully and the sea became calm miraculously. But the cross slipped from his grip and fell down into the deep sea. He reached the shores of Seram island the next morning. On the shore, he saw a crab crawling towards him from the sea, carrying, clutched between its claws, the crucifix he lost in the sea. The saint knelt down, praised the Lord and recovered the cross from the crab. He thanked the Lord, kissed the cross and blessed the crab. Popular belief is that the crab developed the mark of the cross on its shell miraculously as the saint blessed it with the sign of the cross. Crabs bearing the cross mark which are found even today in the sea, are believed to be the descendants of the crab that was blessed by the saint for retrieving his cross from the sea. This incident was depicted on the altar at the ceremony for canonization of the saint in 1622.
These special species of crabs bearing the sign of the cross are described as living miracles of the saint and have been powerful instruments to strengthen the faith of many. St. Francis Xavier was one of the founding fathers of the Society of Jesus (Jesuits). He was transformed by the words of Jesus, repeated by St. Ignatius Loyola, "Will a person gain anything if he wins the whole world but loses his life?" {Matthew 16: 26, Mark 8: 36}. St. Francis Xavier is the patron saint of missions, missionaries and sailors. He was called to eternal rest on 2nd December, 1552. The blessed body of this great saint still remains miraculously without decomposition in the Basilica of Bom Jesus at Goa, India. His liturgical feast day is celebrated on the 3rd of December every year.