164 University of California Publications. [zoology. 



salamander, though the snake was hungry, as was proved by its 

 readily eating Batrachoseps and tadpoles, and though the sala- 

 mander was by no means too large to discourage an attack. Each 

 time the Diemyctylus was introduced into the terrarium the snake 

 became alert, moved toward the Diemyctylus and apparently made 

 an examination, its nose coming close to the newt's body, its tongue 

 darting out and in. After that the snake withdrew and seldom 

 showed any desire to repeat the test. On the one occasion when 

 the snake did make an attack it had fasted for eleven days. As 

 soon as the Diemyctylus was introduced the Thamrophis made 

 only a hurried examination, then seized the newt by the middle, 

 and, working its jaws from side to side moved up nearly to the 

 head. Then, instead of swallowing its captive, the snake slowly 

 relinquished its hold and finally dropped its intended victim. 

 That this foi-etaste of its anticipated meal was enough to satisfy 

 the Thamnophis seemed clear, for it went about for an hour after- 

 wards, opening its jaws very wide at frequent intervals, as if 

 trying to get rid of a bad taste; and the lesson was learned so 

 thoroughly that in the three remaining trials it took no notice of 

 the newt. 



With Plethodon the tests have been most instructive in con- 

 nection with the ring-necked snake, Diadophis amabilis. This is 

 a favorable subject for experiment, for, its haunts being the same 

 as those of the salamander, it is no doubt a natural enemy. I 

 had made numerous trials with the Plethodon, before finding 

 a Diadophis, such as forcing a frog and a garter snake to swallow 

 either the tail or the entire animal. On one occasion a garter 

 snake, left with two small Plethodons, devoured both, but 

 these specimens were both small and without tails, consequently 

 could be eaten with impunity. In every case of forced feeding 

 both frog and snake went through the act of gagging after eating, 

 and one snake, after three days, regurgitated the whole sala- 

 mander with only a portion of the head digested. The same 

 frog ate a piece of raw meat of equal size and voluntarily took a 

 number of tiny toads without gaping. On the other hand it is 

 not safe to say that the gagging was in every case due to a 

 bad taste or that the regurgitation was the result of disagreeable or 

 poisonous qualities. The violent methods of feeding in these 



