The term rhinencephalon of Crosby refers to a composite substructure of the endbrain. Identified functionally with the olfactory system, it is defined on the basis of comparative anatomy to include the olfactory bulbs, the olfactory tract, the anterior olfactory nucleus, the olfactory tubercle, the subcallosal gyrus, the diagonal band, the nucleus of the diagonal band, the piriform cortex, the parahippocampal gyrus, the hippocampal complex and the cingulate gyrus ( Crosby-1962 ). For a thorough review of the history and multiple uses of the term "rhinencephalon" see Anthoney-1994. Updated 8 Jun 2024.