No. 438.] AMBL YSTOMA TIGRINUM. 



387 



However, not death, but early metamorphosis is the probable 

 explanation of this early disappearance. Metamorphosis fre- 

 quently takes place early in the season, even in June. I have 

 taken small specimens in metamorphosis as early as June from 

 ponds with a depth of water from four to six feet. A careful 

 series of observations, in the case of a single pond, showed the 

 period of wholesale met:miorphosis to occur, in this instance, in 

 the latter half of August. Yet in this case unusually heavy 

 August rains had raised the pond to its maximum height and 

 even caused considerable overflow. In spite of repeated search 

 at appropriate times and places, no Amblystomae have been 

 found in metamorphosis on the mud of drying ponds. That 

 they are so found in other localities the writer knows from 

 childhood experience, as well as from report and record. Our 

 ponds are usually too muddy for direct observation, but the con- 

 stant use of the dip net has shown me that these larvae undergo 

 metamorphosis in a considerable depth of water, preferably about 

 three feet. My field notes show but few instances of single 

 specimens in metamorphosis taken from the shallow borders of 

 ponds; many more from deeper water, even up to six feet. In 



before the metamorphosis was quite complete. 



The second point at which I have failed to make my observa- 

 tions tally with the statements of others is in regard to the habit 

 of rising to the surface for air. It has been stated that rising to 

 the surface for air, or at least the more frequent rising, pre- 

 cedes or ushers in, metamorphosis. I have been favorably situ- 

 ated for the observation of this habit, and have followed its 



cessation, rebeginning, etc.; but whatever the significance of 

 this strange and intricate phenomenon may be. it is certain that, 



sis. It may begin and, within a day or two, become incessant 

 with larvae far too small for metamorphosis, under any condi- 



well aerated clear water, ten feet in depth, so incessantly playing 

 to the surface that the water seemed as if rained upon with large 

 drops at the beginning of a shower. Day after day I found them 



