14 journal of Comparative Neurology and Psychology. 



had actually spread back and had not simply moved with the 

 area on which it was situated. Both these conditions are found, 

 as will be shown in the analysis of the groups. This rule seems 

 to be particularly applicable to the solid parts of the head and 

 body, rather than to the gills, where the spreading can be deter- 

 mined segmentally much more accurately. 



3. THE ORAL, PHARYNGEAL AND CUTANEOUS GROUPS. 



In order to ascertain whether taste buds appear first in areas 

 that are undoubtedly ectodermic or in areas that are endodermic, 

 buds were classified roughly into three groups: 



{a) The oral group, comprising buds lying on the anterior 

 portion of the mouth, both roof and floor, and extending as far 

 back as and including the proximal hyoid arch and suspensorium. 



(b) The pharyngeal group, comprising buds lying on the roof 

 and floor of the pharynx, on the gills, and extending as far for- 

 ward as and including the ventral portion of the hyoid arch and 

 extending posteriorally into the oesophagus. 



(t) The cutaneous group, including all buds lying on the dorsal 

 and ventral portions of the head and on the barblets, operculum 

 and posterior portions of the body back of the operculum. This 

 group is, in the anterior portion of the head at least, a continua- 

 tion of the anterior oral group, and is catalogued separately for 

 the purpose of a preliminary survey only. 



In tabulating the buds of the barblets it was not practicable, 

 of course, to place them in the sections in which they were found, 

 since they might lie in almost any position, nor in the sections in 

 which the proximal portions lie, since the base varies in size at 

 difi^erent ages and always occupies a number of sections; nor was 

 it possible to ascertain accurately their number in later series, 

 since they are very numerous. The barblet buds are not in- 

 cluded in Table II, since the main object ot this tabulation is to 

 show the place of first origin and the rate of progression from this 

 point. They will be given in separate tables and discussed fully. 

 The buds of the barblets should be added to the total ot Table II 

 to ascertain the exact number of buds in a given series. 



From Table III it will be seen that buds appear simultaneously 

 in the anterior portions of the mouth (really on the inner surface 

 of the lips and breathing valve, which cannot be distinguished 

 at this age) and in the pharynx. The buds of the pharyngeal 



