1. Atz, J.W. (1952) Narial breathing in fishes and the evolution of internal nares. Q. Rev. BioL., 27, 366–77.
2. Bakhtin, E.K. (1976) The morphology of the olfactory organ in some fish species and its functional interpretation. Vop. IkhtioL., 16, 867–88. (In Russian)
3. Bakhtin, E.K. (1977) Peculiarities of the fine structure of the olfactory organ of Squalus acanthias. Tsitologiya, 19, 725–31. (In Russian)
4. Bannister, L.H. (1965) The fine structure of the olfactory surface of teleostean fishes. Q.J. microsc. Sci., 106, 333–42.
5. Beard, J. (1886) The system of branchial sense organs and their associated ganglia in Ichthyopsida. A contribution to the ancestral history of vertebrates. Q.J. microsc. Sci., 26, 95–156.