No. 549] A CASE OF POLYMORPHISM 



529 



The cannibals can and do ingest their full-sized con- 

 geners, Imt they are by no means successful in every at- 

 tack. One may observe them, with empty stomachs, 

 making scores of furious but futile attempts at capturing 

 their adult neighbors. It is largely the young hump- 

 bearers which, though nearly full grown, fall ready vic- 

 tims to the all-embracing coronas of the cannibals. Thus 

 it follows that any reduction of the food supply of the 

 lesser type immediately impoverishes the larger one as 

 well. The consequences of this are curiously dissimilar 

 in different cases, although always one of two results in 

 tervenes. The cannibals may become even more canni- 

 balistic, destroying the entire humped population of all 

 ages, and their own young as well, until the culture is 

 finally obliterated by the death, from old age, of a few 

 veterans which are without further food supply. This 

 has happened again and again in my large culture 

 dishes. 7 In a few cases it has happened that a culture, 

 when at the point of extinction, would again revive by the 

 multiplication of the humped form. This is due to the 

 fact that the last starving cannibals, reproducing, as 

 they always do, both their own type and the humped type 

 as well, fail to eat up perhaps a single member of their 

 humped progeny, which then survives to start a new cycle 

 under less strenuous surroundings. I have carefully fol- 

 lowed this decline and survival as thus stated. 



In about half of the cases, however, a very different 

 effect is registered upon the campanulate form by the 

 lessening food supply and the falling numbers of the 

 other type. It undergoes a considerable degeneration, 

 which may perhaps reduce it to the form from which it 

 arose, although I have not been able to fully demonstrate 

 this. But forms more or less intermediate are produced 

 by the starving cannibals. The trophi remain typical, 

 but the enormous coronas, as well as the breadth of the 

 entire animal, are much reduced. In the single instance 



