BEHAVIOR OF VERTEBRATES 427 



The normal dog follows the food in all directions with pro- 

 nounced movements of the eyes and muzzle. But where there 

 are marked deficiencies in vision, as in the lower half of the 

 campus oculi sinistri, the definite following movements suddenly 

 cease, but begin again when the food is brought within the 

 visual field. At the moment of disappearance, seeking move- 

 ments of the eyes and muzzle may be noticed. This method 

 gives quick orientation where the deficiencies brought about 

 by cortical extirpation are great. The third auxiliary method 

 he calls the "Auseinanderfuhmngsmethode." Two bits of food 

 are first held above the dog's nose and are then drawn apart in all 

 directions; sometimes both are drawn apart simultaneously, 

 while at others one remains fixed and the other is moved away. 

 (At least so I understand " — dass zwei Nahrungsstucke zuerst 

 iiber der Nase gehalten und dann verschiedenen Richtungen 

 einzeln oder gleichzeitig auseinander gefuhrt werden"). 



For the results of the experiments on extirpation of the cor- 

 tical areas and for the anatomical findings the original paper 

 must be consulted. 



AUDITION 



Fish. Parker (20) finds that the noise of motor boats is 

 extremely faint under water and has almost no influence upon 

 the movements of fishes engaged in feeding. Single explosive 

 sounds like that of the report of a gun are likely to startle the 

 fish and cause a temporary cessation of feeding. 



Some tests made by Dr. A. G. Mayer, Dr. Goldfarb and the 

 reviewer in Tortugas during the past summer on the distance 

 at which sounds produced under water may be detected by a 

 person with head and body immersed do not bear out Parker's 

 contention that sounds heard under water are extremely faint. 

 Dr. Mayer tapped two pieces of coral together under water 

 while Dr. Goldfarb and the reviewer swam away. Up to a 

 distance of appro ximately 100 yards the faint sound made in 

 the above manner was distinctly heard by both observers with 

 head and body immersed. At this distance Dr. Mayer tapped 

 the two pieces of coral together in the air. They were clearly 

 audible to the observers with heads in the air, but unfortunately 

 we did not try the experiment of giving the sound in the air 

 with the observers' heads immersed. 



In Parker's work no mention is made of the possibility of 



