74 ^Journal of Comparative Neurology and Psychology. 



But in Gadus the movement is quite different, since the food 

 stimulus is under the center of the body when it is detected. 

 Before the food can be taken, the fish must check the forward 

 movement and back up until the mouth has reached the object. 

 This involves a very precise movement of the pectoral fins in par- 

 ticular, and if the prey be living it must be very rapidly done. 

 These features, taken in connection with the more active life of the 

 gadoids in general, are sufficient to account for the short-circuiting 

 of the reflex path between the gustatory root of the facial nerve 

 and the ventral cornu of the spinal cord, so that a gustatory stim- 

 ulus on the fins alone may cause the reaction promptly without the 

 cooperation of the tactile centers. 



We have then, in summary, the* following striking series of 

 structural adapations correlated with the appearance of taste 

 buds in the outer skin of fishes. Such buds occur in fishes gen- 

 erally in the mouth and on the lips, the latter being innervated 

 by the facial nerve. Landacre has shown in a recent embryo- 

 logical research ('07) that in Ameiurus the cutaneous buds appear 

 first in the region of the lips and then progressively farther 

 caudad. It is probable that this was also the order of their 

 appearance phylogenetically, a supposition which is supported by 

 the course of the branches of the facial nerve which supply these 

 cutaneous buds in the adult. As these facial gustatory nerves 

 increased in importance, especially those from the barblets, cen- 

 tral correlation was required with the tactile and motor centers 

 for the barblets in the region of the trigeminus. This anatomical 

 connection finally caused the cutaneous gustatory center to move 

 forward from the vagus region into the facial, and a further corre- 

 lation was effected between the gustatory and tactile centers by 

 means of the descending secondary gustatory tract from the facial 

 lobe to the funicular nuclei. 



In the gadoids the fins, particularly the free pelvic fin rays, 

 serve as motile organs of tactile-gustatory sensation. The gusta- 

 tory innervation is as before through the facial nerve, but the 

 tactile through spinal nerves which enter the brain behind the 

 vagal lobes. Accordingly, the somatic gustatory center does not 

 migrate forward, but remains stationary, and the secondary gusta- 

 tory path passes from it directly to the motor centers of the spinal 

 cord instead of first to the tactile correlation center. This pro- 



