THE DEVELOPMENT OF FASCIOLARJA. 145 



set free. In the experiments which I made all but two or three 

 larva: in each of a large number of capsules were forcibly in- 

 jured, and their undigested contents offered to the uninjured, 

 larva:. These, although fully distended, in every case began to 

 devour the additional eggs offered them, and in three or four 

 days had mastered twice as man}' as had before fallen to their 

 respective lots. One experiment, which was particularly suc- 

 cessful, consisted in an attempt on my part to ascertain whether 

 one larva would eat all the eggs which had been taken in by its 

 competitors. This was accomplished by first injuring two of 

 these and waiting until the extra number of eggs had been dis- 

 posed of. Then two of the remaining larvae were injured and the 

 eggs which they contained --some of which had been swallowed 

 once and others twice -- were offered to the three uninjured in- 

 habitants of the capsule. After this second offering of eggs was 

 disposed of, two of the remaining three larvae, which had grown 

 to more than double their original size, were injured, and their 

 contents offered to the sole survivor. This individual, already 

 excessively gorged, began to ingest the eggs which had been 

 swallowed from one to three times ; unfortunately the elasticity 

 of its body was not equal to the undertaking and the larva burst 

 from over-eating before it had finished. 



Over-feeding comparable to what happened in these experi- 

 ments may take place without human interference. It is easy to 

 see how the natural disturbances to which the capsules are sub- 

 ject might be sufficiently violent to burst some of the larvae whose 

 contents then would be devoured by the survivors. I am con- 

 vinced that this actually takes place, since the larvae in those 

 capsules which contain only two or three are always much larger 

 than the average. From these observations and experiments I 

 believe that the number of eggs secured depends on promptness 

 and structural aptitude for seizing and swallowing. 



II. THE EXTERNAL AND THE ACCESSORY EXTERNAL 



KIDNEYS OF FASCIOLARIA. 



Develop incut. - The external kidneys, also known as "excre- 

 tory cells" (Conklin) or " subvelar masses" (Osbore) and very 

 generally called " Urnieren " by German writers, originate early 



