A brief review of the comparative anatomy of the lateral geniculate body of mammals is presented. Emphasis is placed on cytoarchitecture in relation to fiber connections as revealed by modern experimental silver impregnation techniques. The ventral nucleus of the lateral geniculate body has been most commonly subdivided into an internal and an external division. Only rarely have these divisions been further parcellated. A classification of the currently known patterns of organization found in the dorsal nucleus of the lateral geniculate body is presented. This classification is based on cytoarchitecture and the degree and particular pattern of segregation of ipsilateral and contralateral retinal input. Overt lamination in this nucleus appears to be found in those mammals specialized for flight, gliding, rapid movement through the trees, or rapid movement on the ground. It is clear that lamination has evolved independently many times. Animals now known to possess this characteristic share a common functional challenge: the need for rapid evaluation of spatial relations including depth perception.