Structure, development, and evolutionary aspects of the peripheral olfactory system

Abstract

The morphology of the olfactory organ in fish has fascinated scientists for a long time. At the turn of the 18th to the 19th century, investigators were already attracted by the formation of olfactory lamellae in fish. From the second half of the 19th century, extensive comparative investigations followed (comprehensive historical review: Kleerekoper, 1969, 1982). Schultze (1863) was the pioneer of studies on the histology of the olfactory epithelium of vertebrates, including fish. He found two types of cells, epithelial and sensory, the latter of which seemed to be the peripheral end of the olfactory nerve. A new epoch of histology began with the introduction of the electron microscope. Using this technique the first results from the olfactory epithelium of fish were obtained by Trujillo-Cenoz (1961). The last review of the morphology of the peripheral olfactory organ in fish (Yamamoto, 1982) was focused on teleosts. This chapter deals also with non-teleost fish. Aspects of ontogeny, growth, adaptation, and evolution of the peripheral olfactory organ are included.