f)92 GEOB'FREY LAPAGB 



seemed wise to reconsidt^r the data. When this was done it 

 became obvious that the spheres were not endogenous buds. 



Throughout my stained preparations I have never seen any 

 signs of change in the nucleus, either in the amoeba or in the 

 sphere, although I have very carnfully searched for such eyto- 

 logical evidence of the formation of a bud. Whatever the size 

 of the amoebae or of the spheres might be, the nuclei of both were 

 always in the same condition, that is to say, in the ' resting ' 

 condition which has been figured ; the nucleus of the sphere 

 was always similar in structure to that of the amoeba. 



I have tried hard to find evidence of the division of the 

 nucleus of the amoeba to form the nucleus of the sphere, or 

 evidence of the formation of the latter from chromidia extruded 

 by the nucleus of the amoeba. Indeed, under the influence 

 of the hypothesis of endogenous budding I have often thought 

 I have seen chromidia, just as I have often thought I have 

 seen in this and in other forms, centrosomes, centrioles, 

 and other structures, when I have wanted to find them. But 

 these structures have, on re-examination, proved to be, in 

 every case, either figments of my o^^^l imagination based upon 

 improperly differentiated slides, or artefacts. I am now 

 convinced that there is no evidence, of any sort or kind, of 

 changes in the nuclei either of the amoebae or of the spheres 

 in my slides. 



If endogenous budding had been going on to the extent that 

 the abundance of the spheres would suggest, some evidence 

 of the mode of formation of their nuclei from the nuclei of the 

 parent amoebae would have been seen. It is true that even 

 binary fission is seen only very rarely, as Doflein also points 

 out (9). In my slides I have seen only two or three dividing 

 amoebae, and in those the two daughter nuclei had already 

 returned to the ' resting ' condition. This is the only evidence 

 that I have seen, either in the stained or in the living material 

 of any reproductive processes whatever. 



It is to be remembered, moreover, that when the endogenous 

 buds are being formed in an organism like the Suctorian 

 Dendrocometes paradoxus, the contractile vacuole 



