In the first gallery of "Marlene Dumas: Measuring Your Own Grave" at the Museum of Contemporary Art, Los Angeles, hangs an oil painting of a washy gray skull set against a densely black background. The picture of the skull is in profile and takes up most of the canvas, which measures a little less than 4 x 5 ft. In the centuries-old tradition of vanitas, such still-lifes are meant to remind viewers that no amount of silver plate and glassware can stave off the inevitable. In the 17th and 18th centuries, vanitas pictures were among the commonest paintings produced by Netherlandish artists, and Dumas has lived in Amsterdam since 1976. This particular depicted skull, however, belonged to a woman. It is a memento mori for a way of seeing the world.