Named after Luiz Cruls - Brazilian astronomer (1848-1908).
Cruls is an impact crater in the Eridania quadrangle on Mars at 42.91° S and 163.03° E. and is 87.89 km in diameter. Evidence of previous glacial activity is evident in images. (wikipedia entry)
A crater is a circular depression likely created by an impact event. On Mars large craters are named after deceased scientists, writers and others who have contributed to the lore of Mars. Small creaters (less than 60km) are named after small towns and villages.