ABSTRACT
In higher mammals, such as carnivores, primates, and man, the brain has developed sufficiently to make effective use of sight and hearing. It is not surprising that the occipital lobe in primates seems more prominent than in most other mammals. There is a great deal of work ahead in determining the range of patterns of visual system organization present in the visual systems of primates and other mammals as well as in understanding the functional significance of these patterns. Prosimian primates, living and fossil, have relatively few cerebral cortical sulci when compared with anthropoids and many of them have a longitudinal orientation. Radinsky has noted that endocranial casts of fossil primates indicate that expansion of the frontal lobe lagged behind that of the rest of the cortex, for as recently as the Early Oligocene the frontal lobes were relatively smaller than those in almost all modern prosimians.
