4 /. H. Powers 



if a harmony exists, it is a harmony with the general principles 

 only, requiring quite new applications. Cope had indeed, in 

 common with many others, a thoroughly wrong idea of meta- 

 morphosis itself. He viewed the process as one, not only initiated 

 by external conditions, but controlled throughout by them; exter- 

 nal conditions might initiate, accelerate, retard, and even reverse 

 metamorphosis. At least Cope embodies in his work approvingly 

 the observations and interpretations of Schufeldt, which go as far 

 as this. Moreover, Cope and Baird seem to assume that meta- 

 morphosis may be interrupted or arrested, not only as a whole, 

 but with regard to almost any single character or group of char- 

 acters. Sexually mature adults may thus result, showing the 

 most varying degrees of larval relationship. I find such a view 

 strongly opposed to the facts. Variable as is the species as a 

 whole, and variable as are the age and the size at which meta- 

 morphosis may take place, the process as such is relatively uni- 

 form ; it is, so to speak, a violent one, initiated, as I have shown 

 in the article above referred to, usually by a check in food sup- 

 ply, but when it once begins, it runs its course well-nigh re- 

 gardless of external conditions. Its rate may be retarded con- 

 siderably by lowered temperature and by certain other conditions, 

 but, barring extremely rare exceptions and such as can hardly 

 occur in nature, the animal issues from its period of change, be 

 this rapid or slow, having undergone about the same degree of 

 transformation. The transference of larvae from a warm pond in 

 August to the darkness and low temperature of a ^ deep covered 

 cistern has often yielded me adults almost indistinguishable from 

 those that metamorphosed simultaneously in the pond. If color 

 patterns were frequently modified, structures were usually not 

 affected. 



Indeed, so far are my observ^ations from sustaining Cope's view 

 of varying metamorphosis as the source of adult variations, that I 

 find the very opposite to be the general rule : metamorphosis is a 

 leveling process, tending to produce uniformity, not diversity. 



The larva may, in perhaps something more than a figurative 

 sense, be said to be the parent of the adult. Metamorphosis is a 

 kind of rebirth and redevelopment, and during its accomplishment 



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