270 MANTON COPELAND 



were collected in the early part of August. Admitting of identi- 

 fication were four snails of two genera, one water-boatman 

 (Corisa), one caddis-worm, several midge larvae (Chironomidae) 

 and three amphipod crustaceans. Since Diemyctylus feeds 

 upon such actively moving organisms as crustaceans and cer- 

 tain insects it must in many instances have no time to use its 

 olfactory organs, but would depend wholly on its powers of 

 vision and quickness of action in securing its prey; and in 

 consequence of such experience in nature it might be expected 

 to snap at a bit of moving filter paper in the aquarium. On 

 the other hand, the presence of insect larvae concealed in their 

 cases, or snails within their shells, may possibly have been 

 recognized by the sense of smell. 



REESE'S EXPERIMENTS 



Seme of the work of Reese on the reactions of Diemyctylus 

 to chemical stimuli, together with certain conclusion, may be 

 briefly reviewed. Reese records the results of experiments 

 planned to show whether sight or the telaesthetic sense is the 

 one used by the newt in finding food. The animals were first 

 tested by comparing their reactions to pieces of meat with those 

 to inedible objects such as cloth, cotton and filter paper held 

 in forceps. Secondly, the effect of meat juice squirted over the 

 snout was studied. 



In testing the animals by the first method the motion factor 

 enters, a thing which evidently the author did not attempt to 

 control. On page 191 he writes: "It would follow small taste- 

 less objects of various colors and would often seize them, but 

 usually disgorged them immediately," and after experimenting 

 with meat juice squirted over the nostrils concludes: " In secur- 

 ing food, then, it is probable that Diemyctylus uses both sight 

 and the telaesthetic sense, perhaps the latter more than the 

 former." Unquestionably both sight and smell are used in 

 obtaining food, and I believe I have shown the part played by 

 each. The seizing reaction undoubtedly was called forth in 

 many instances not so much by sight of the object as by sight 

 of it in motion. If the animals had been tested with stationary 

 objects by methods such as I have described, their marked 

 ability to discriminate perfectly between the edible and inedible 

 prior to seizure would in all probability have been demonstrated. 



