The generalized Rouse equation derived by Schweizer(1) is applied to chains in the crossover region between Rouse-like behavior and reptation-like behavior. A self-consistent scheme takes into account the coupling of single chain motion and the decay of density fluctuations in the polymer matrix. It will be shown that this model may be understood as a generalized bead-spring model, comprising beads with a frequency-dependent mobility and effective springs modified by their surroundings. The correlation functions of normal coordinates are investigated as a function of frequency, and strong qualitative deviations from the Rouse case with respect to the distribution of relaxation times are found. On this basis, general trends concerning viscoelasticity sue elucidated and relevant time scales are discussed.