Otis T. Mason describes a basketry bolo (toilet or knife) case of the Jacanes (Yacanes) of Basilan Island in the Philippines, held in the U.S. National Museum. He covers its structural parts: a carved wooden footing and bottom, a body of bamboo splits woven in four directions over a hexagonal foundation, a complex hooped border with rattan lace work and Malay knots, and rattan carrying strips. He also describes the Malay knot and the decoration by carving, staining and smoking. Illustrated with photographs and line drawings of the case, its weave and its border.