66 SMELL, TASTE, ALLIED SENSES 



Similar experiments on the killifish (Fundulus) gave 

 like results Parker (1911). Here, however, the olfac- 

 tory organs were excluded, not by cutting the olfactory 

 tracts, but by stitching up the anterior nares. As a re- 

 sult of this operation the fish no longer responded to hid- 

 den food, but quickly reacquired this power after the 



FIG. 15. Ventral view of the head of a Hammer-head Shark (Ceatracion) showing the 

 olfactory pits (o) widely separated. After Carman, 1913, Plate 1, Fig. 2. 



anterior nares had been reopened. These results were 

 confirmed in work on the dogfish, (Mustelus), by Sheldon 

 (1911) and on the swellfish, (Spheroides), by Copeland 

 (1912). Sheldon closed the nares of the dogfish with 

 cotton plugs and, in 1914, I showed that when only one 

 nostril is thus plugged, the fishes turn persistently to- 

 ward the side of the open nostril. Such responses 

 indicate that in the seeking of food under normal con- 

 ditions, dogfishes, and probably other fishes as well, turn 



