1921] NATURAL SCIENCES OF PHILADELPHIA 137 



ole, after having acquired an immense size, ])urst and disappeared 

 (Plate VII, fig. 44, d); the leucosine globule became divided into 

 two parts, one of which passed to each of the new individuals just 

 when the bridge between them was breaking (Plate VII, fig. 44, e) ; 

 and the two new amoebae slowly went their way (Plate VII, fig. 44, 

 /). The whole process, from a to/, had lasted twenty minutes. At no 

 time had it been possible to detect the least indication of a flagel- 

 lum. Scherffel, in the first case he studied, observed (1911, p. 315) 

 that one of the new individuals, long before the separation, already 

 possessed a slowly oscillating flagellum, but later on, when he again 

 had the opportunity to observe a second case of division, he found 

 that neither of the new individuals ever developed any. For my 

 part, I consider it quite possible that in both cases Scherffel had 

 seen rightly: in the first one, the amoeba immediately prepared for 

 the flagellate stage, in the second it remained an amoeba. 



But if this case of division is the only one I could study at length, 

 there is another which I should like to mention, which though not 

 proving successful at last, is indeed hardly less interesting. The 

 amoeba, when found, was already narrowed in the middle, and in 

 possession of two distinct chromatophores, each of them in a F form, 

 but united together by their adjacent extremities, like a W; so firmly 

 united, in fact, that when but a narrow bridge alone separated the 

 two new individuals, one of the chromatophores, which should have 

 entered the new individual, had not been able to follow the move- 

 ment, and remained in what we might call the "old" individual, 

 while the "new" animalcule, quite deprived of any green matter, 

 was just going away. A very narrow^ bridge, however, a mere 

 protoplasmic thread, was still uniting the two amoebae; but danger 

 was coming, an air-bubble approaching more and more, and to get 

 rid of it I added some water to the side of the cover. The bubble 

 retracted, but, as a consequence of a violent temporary shaking, 

 the couple seemed to give up dividing, the bridge got wider, and 

 by and by the new pale individual slowly "re-entered" the old one, 

 after a moment a single amoeba was seen, with two chromatophores 

 instead of one. But without that disastrous commotion, certainly 

 an entire separation was quite near, and the new amoeba would 

 have been colorless, just like the specimen which Scherffel once 

 found, and figures on Plate VI of his 1901 work. 



To conclude with Chrysamoeba, I ought perhaps to speak of the 

 encystment. Some observations have been made which allowed 

 curious conclusions, so curious, indeed, that ... it would be 



