Abstract: A disposable flexible disc radial cuvette array has its cuvettes divided into inner compartments and outer compartments by a ramp-shaped wall. These cuvettes are separated from their adjacent cuvettes by dual side walls and have uniform parameters. The annular cuvette array includes an integral opaque horizontal annulus having a first radial series of slots thereon, substantially aligned with the radial centers of the outer ends of the cuvettes, and has a second radially spaced set of slots generally aligned with the side walls. The cuvette walls and array hub portion provide rigidity. The annulus also has an inwardly extending flange covering the outer radial ends of the cuvette, there being formed therein slots open to both the inner and outer compartments. Locating projections extend upwardly from the disc surface in an embodiment adapted to position a rotatable, cuvette numbering, annular ring, the ring being variably, rotatably positionable to provide selectivity of the cuvette numbers.