Current views about the functional organization of memory in the medial temporal lobe of the mammalian brain suggest that the hippocampal formation (HPC) and the perirhinal cortex (PRh) are serial components in a unitary memory system. Contradictory to this view, evidence from numerous studies with monkeys and rats suggest that there are at least two independent memory systems within the medial temporal lobe. It appears that the PRh is critically involved in object-recognition memory, but the HPC does not make a significant contribution to this type of memory. Spatial memory appears to rely on the integrity of the HPC. It is not clear what role, if any, the PRh has in supporting spatial memory. The aim of this thesis was to assess the validity of these two views about the functional organization of memory and the contribution of the HPC and PRh to object-recognition and spatial memory. (Abstract shortened by UMI.)