Chapter VI: The Evidence of the Olfactory Apparatus

Fishes divided into Amphirhinæ and Monorhinæ--Nasal tube of the
lamprey--Its termination at the infundibulum--The olfactory organs
of the scorpion group--The camerostome--Its formation as a tube--
Its derivation from a pair of antennæ--Its termination at the true
mouth--Comparison with the olfactory tube of Ammocoetes--Origin of
the nasal tube of Ammocoetes from the tube of the hypophysis--
Direct comparison of the hypophysial tube with the olfactory tube
of the scorpion group--Summary 218