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