BEHAVIOR OF VERTEBRATES 429 



packets was lost. It was restored when the stitches were re- 

 moved. In cases where the stitches were taken, but where the 

 threads were not drawn up and tied so as to close the aperture, 

 discrimination was not lost. Parker concludes that Fandulus 

 heteroditus uses its olfactory apparatus as an organ with which 

 to scent its food; "i.e., its olfactory apparatus is a chemical 

 distance-receptor of very considerable importance in its daily 

 activities." ' 



Sheldon's (23) work on Selachians is in harmony with that of 

 Parker. When a crab is placed in a pool containing dogfish a 

 few minutes are necessary for diffusion to take place. The 

 dogfish which first happens to swim within three or four feet 

 of the crab turns suddenly as if startled, and swims about now 

 eagerly alert and searches for the food. When within three or 

 four inches of the crab it suddenly seizes it and makes off rapidly. 

 Very little use of vision is noted. The food packet method was 

 tried with convincing results. Packets containing stones were 

 not touched, while those containing crabs were always seized. 

 Packets saturated with the juice of a crab and weighted with a 

 stone were likewise seized. When the nasal passages are closed 

 with cotton wadding coated with vaseline, the fish do not respond 

 to the food stimulus. The wadding produces some disturbance, 

 but this factor was sufficiently controlled by testing fish with 

 one aperture closed. From one to two days after the removal 

 of the plugs fish so treated responded normally again. 



The general conclusion is that Selachians find their food 

 almost exclusively by a sense of smell which is comparable 

 to that possessed by terrestrial vertebrates. 



Birds. Strong (26) takes up the vexed problem of smell in 

 birds from the standpoint of both morphology and behavior. 

 His study of the anatomical features of the olfactory organs in 

 birds leads him to agree with Edinger, viz., that one ought to 

 expect to find evidence of a sense of smell. There is a great 

 variation in the size of the olfactory structures in the different 



1 Since neither Parker nor Sheldon mentions the previous work of Baglioni 

 (Baglioni, S., Contributions experimentales a la physiologie du sens olfactif et 

 du sens tactile des animaux marins., Archiv. Ital. de Biol., 1!)09, 52, 225-230), I 

 cannot help calling attention to the fact that this investigator, on the basis of 

 tests upon the octopus and blind fish (Balistes), urges that these marine forms 

 possess such a chemical sense, and on the question as to whether it should be 

 called smell or taste comes out strongly in favor of calling it smell, since from 

 the standpoint of reaction it is a distance-receptor. 



