1. PAL-carmine stained serial transverse sections of the brains of man, 12 Simiae (6 Catarrhini and 6 Platyrrhini), 2 Prosimiae, 6 Carnivora, 5 Ungulata, 1 Cetacea, 5 Rodentia, 1 Dermoptera, 2 Chiroptera, 3 Insectivora, 4 Edentata, 4 Marsupialia, 2 Monotremata (48 species of mammals in total), 5 Aves and 7 Reptilia or 60 species of vertebrates in grand total were examined.
2. The oval nucleus (GROSSMANN) was demonstrated to represent an independent nucleus distinct from the solitary nucleus in histological finding, fibre connection and phylogenetic development.
3. The oval nucleus is supplied with the greatest part of its afferent fibres from the intermediate nerve and a small part of them from the glossopharyngeal nerve.
4. This nucleus sends out efferent fibres into the cerebellum and the intrapontine motor root of the facial nerve.
5. This nucleus is proprioceptive in nature and probably receives stimuli from the facial muscles in the main.