164 'Journal of Comparative Neurology and Psychology. 



buds are very different from tho^e of the phylogenetically older 

 taste buds within the mouth. In the catfish and carp the prin^ary 

 cerebral center for all of the cutaneous taste buds is the facial 

 lobe, from which secondary gustatory tracts of the typical sort 

 pass out to the visceral motor centers, and in addition a direct 

 secondary path to the funicular nuclei where these gustatory 

 impulses are coordinated with tactile impressions from the same 

 areas of skin." A single path leaves the funicular nuclei for 

 the somatic motor centers, thus serving as a common reflex 

 path for both tactile and gustatory impulses from the skin. In 

 the cod'' the cutaneous taste buds effect somatic motor connections 

 in an entirely different way, passing directly from the equivalent 

 of the facial lobe into the fasciculus longitudinalis medialis and 

 thence to the somatic motor nuclei, indicating that the cenogen- 

 etic connection of the taste buds which act as exteroceptors with 

 somatic motor centers has been acquired independently in the 

 gadoids and the Ostariophysi. 



The interesting point in this connection is that within the group 

 of teleosts taste buds, which typically in fishes act as interoceptors, 

 have secondarily acquired exteroceptive functions, and parallel 

 with this change a new central reflex path has been established 

 between the primary centers of cutaneous (exteroceptive) taste 

 and the somatic motor centers. It is probable that at a much more 

 ancient period in the phylogeny of vertebrates an analogous dif- 

 ferentiation took place in the primordial unspecialized chemical 

 sensory apparatus, one part becoming a typical interoceptor (gus- 

 tatory apparatus) and establishing its most direct central reflex 

 connections with the visceral muscles of mastication, deglutition, 

 etc., and another part becoming a typical exteroceptor (olfactory 

 apparatus) and early establishing direct central reflex connec- 

 tions with somatic muscles of locomotion, eye movements, etc., in 

 addition to the visceral motor reflexes characteristic of a visceral 

 system. 



It should be expressly stated that the claim is not made that all 

 anatomical differences between the organs of smell and taste are 

 explained by this principle, but only that in this way the direction 



* C. JuDsoN Herrick: On the centers for taste and touch in the medulla oblongata of fishes. Journ. 

 Comp. Neurol, and Psychol., vol. 16, no. 6. igo6. 



^ C. JuDsoN Herrick: A study of the vagal lobes and funicular nuclei of the brain of the codfish. 

 Journ. Comp. Neurol, and Psych., vol. 17, no. 1. 1907. 



