The shells on this Kuba Belt look like the venomous predatory Cone Snail Shell. They have a venomous barb that comes out of the opening and injects poison! But these shells are widely collected and admired- especially the ones with a type of triangular "fractal" patterning.
Bead lover, collector since Age 15, semi-retired had wholesale/retail bead, folk art, tribal art store Lost and Found Gallery for 25 yrs. in DT Greensboro, NC