Walter Holbrook Gaskell

“ The two olfactory antennæ of the crustacean have combined together to form a hollow tube at the base of which the mouth of the animal is situated, so that the food passes along this olfactory passage before it reaches the mouth. This organ is often called after Latreille, the camerostome, sometimes the rostrum; it is naturally median in position and appears, therefore, to be an unpaired organ; its paired character is, of course, evident enough, for it is innervated by a pair of nerves, and these nerves, as ought to be the case, arise from the supra-œsophageal ganglia. ”

“ In all vertebrates the nose is double and opens into the pharynx, until we descend to the fishes, where the whole group Pisces has been divided into two subsidiary groups, Monorhinæ and Amphirhinæ, according as they possess a median unpaired olfactory opening, or a paired opening. ”

“ At the front end of the body is seen the median eye (ce.) , o is the mouth, Ph. the pharynx, œs. the narrow œsophagus, compressed between the supra-œsophageal (supr. œs.) and infra-œsophageal (infr. œs.) brain mass, which opens into the large alimentary canal (Al.) ; Olf. pass. is the olfactory passage to the mouth, lined with thick-set, very fine hairs, which spring from the hypostome (Hyp.) as well as from the large conspicuous camerostome (Cam.) , which limits this tube anteriorly. ”