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THE AMERICA X XA TURA LIS T. [Vol. XXXV 1 1 . 



moist surface, under large split sponges raised just enough to 

 give the larvae sufficient room. The sponges were kept wet. 

 In this situation the two larvae which showed signs of metamor- 

 phosis when taken slowly completed the change, and one other, 

 one of the smallest in the lot, after weeks of hardihood in what 

 appeared like a most unnatural and unfortunate existence, under- 

 went still more slowly, an abnormal metamorphosis. The details 

 of this metamorphosis and its final results, both of which I have 

 occasionally had repeated under similar circumstances, are very 



that they appear to me to indicate that metamorphosis by early 



and, in a state of nature, would seldom produce an adult capable 

 of survival, even if the metamorphosis was itself successfully 

 passed The other nine larvae, taken from beneath the plaster 

 and placed beneath the wet sponges, all died, seven of them 

 without showing any signs of true metamorphosis, although 

 several withstood their terrestrial conditions for many days. 



At this point and in connection with the last-mentioned larvae, 

 I wish to protest against what seems to me a careless and well 

 nij,] { 1 nable misinterpretation of certain very simple facts 



withering of the gill-tips and fringes and the like reduction of 

 the dorsi-ventral fin fold. Again and again in the literature of 

 this subject it is evident that observers and experimenters have 

 looked upon these changes as the natural beginnings of true 

 metamorphosis. That a novice should so consider them is nat- 

 ural enough, but how an observer, broadly and minutely conver- 

 sant with the facts of amphibian metamorphosis could so 

 interpret them the writer is at a loss to know. The organs in 

 question do of course suffer when exposed to the air, even to 



seven larvae, which, in the above trial, died before metamor- 

 phosis had begun did take on a somewhat dilapidated appearance 

 before they succumbed. The gills were more or less shrunken 



too, had lopped to one side like a wilted plant, and its margin 

 was uneven and somewhat withered. But these changes, high 



