[Problem of homologization of the cerebral neocortex in cetaceans]

Homologization of the cerebeal neocortex of the cetaceans was performed by comparison of macro- and micro-signs of the structural organization of the cerebral cortex of cetaceanson the one hand and comparison with the same data on the cerebral cortex of ungulates, carnivores and primates. The degree of homology of main fissures and convolutions of the brain of the cetaceans was shown to differ very markedly from the brain of carnivores and priimates. Besides, the complex of macroscopic and cytoarchitectonic characteristics as compared with earlier data on the structural organization of the new cortex of the dolphin (1969,1970) permitted identification of a new type of the cortex which is characteristic only of cetaceans andnot of the ground mammals.