Many models of concurrency and concurrent programming have been proposed; most can be categorized as either task-parallel (based on functional decomposition) or data-parallel (based on data decomposition). Task-parallel models are most effective for expressing irregular computations; data-parallel models are most effective for expressing regular computations. Some computations, however, exhibit both regular and irregular aspects. For such computations, a better programming model is one that integrates task and data parallelism. This report describes one model of integrating task and data parallelism, some problem classes for which it is effective, and a prototype implementation.