736 



SCIENCE 



[N. S. Vol. XXV. No. 645 



(ectoderm) and on the endoderm of the 

 first three gill arches. Buds always spread 

 posteriorly from these places of origin by 

 discontinuous groups. Those of the 

 pharynx spread back into the oesophagus 

 and are continuous with the buds on the 

 last gill arch. Those of the anterior oral 

 cavity spread back in the mouth by dis- 

 continuous groups until they reach the 

 area occupied by the pharyngeal buds and 

 they also spread back on the outer surface 

 of the body by discontinuous groups until 

 they reach the posterior portions of the 

 body. 



No buds spread from the pharyngeal 

 group to the outer surface of the body. 

 The first taste buds to appear on the outer 

 surface are continuous with those just in- 

 side the lips. All the remaining buds 

 appear in discontinuous groups determined 

 partly by the distribution of the rami of 

 the V. and VII. nerves, but not entirely 

 so. There are six well defined groups of 

 buds on the outer surface of the body and 

 two in the anterior oral cavity distinct 

 from the dorsal and ventral lip buds. 



The appearance of buds in the oral and 

 cutaneous areas in detached groups spread- 

 ing from anterior to posterior seems to 

 indicate the order in which specialized com- 

 munis fibers reach the surface through 

 rami of the V. and VII. nerves. A com- 

 parison of the rami bearing fibers in 

 Ameiurus with other types shows a very 

 great degree of variability in the genicu- 

 late ganglion of the VII. nerve as to the 

 number of rami through which it may send 

 communis fibers and as to the time at which 

 it sends them in Ameiurus. The func- 

 tional needs of the organism, such as 

 changes in the methods of seeking and 

 locating food, seem to determine the direc- 

 tion of spreading and also to be more im- 

 portant factors in determining the manner 

 of appearance {i. e., in detached groups) 

 than the mere anatomical arrangement of 



trunks and rami of the nerves, so that the 

 discontinuous groups may be designated as 

 functional groups. 



The Central Beflex Connections of Cutan- 

 eous Taste Buds in the Codfish and the 

 Cat-fish, An Illustration of Functional 

 Adaptation in the Nervous System: C. 

 JuDSON HJEERicK, Deuison University. 

 The taste buds which occur in the outer 

 skin of siluroid and gadoid fishes have 

 been thoroughly studied anatomically and 

 physiologically, their innervation worked 

 out and their central reflex connections 

 compared with those of the tactile nerves 

 from the same cutaneous areas. The peri- 

 pheral gustatory and tactile nerves of the 

 cod and the catfish are the same in prin- 

 ciple, with the exception of the location of 

 the most sensitive areas used in the locating 

 of food. This area is on the barblets of 

 the catfish, but on the filiform pelvic fins 

 of the gadoids, particularly the smaller 

 forms, like the hake and tom cod. Cor- 

 related with this difference is a striking 

 difference in the course of the secondary 

 gustatory tracts for nerves coming from 

 the cutaneous taste buds. In the catfish 

 the facial gustatory center has migrated 

 forward for ease of correlation with the 

 tactile and motor centers of the barblets, 

 jaws, etc., and there is a broad connection 

 between this facial lobe and the general 

 tactile center in the funicular nuclei, 

 whence a common motor reflex path serves 

 to put both sense organs into relations with 

 the motor centers. In the cod there has 

 been no forward migration of the facial 

 lobe, because the tactile nerves from the 

 most sensitive area come in behind the 

 vagal lobes by way of the spinal nerves. 

 And the secondary gustatory path from 

 the terminal nucleus of the cutaneous taste 

 buds does not connect with the tactile cor- 

 relation center, but passes directly to the 

 motor centers. This short-circuiting of the 

 reflex path from cutaneous taste buds is 



