AMEBOID MOVEMENT 43 



other words, the peculiarities of mitotic processes have not been 

 found to be correlated with characters in the somatoplasm. It is 

 to be remembered however that all living organisms, with the ex- 

 ception of some of the bacteria, are classified with respect to their 

 external characters, and that in almost all organisms the number 

 of visible and demonstrable specific characters becomes rapidly 

 greater as ontogenetic development proceeds. 



2. There is considerable disagreement among the investigators 

 of the nuclear phenomena of amebas as to the actual events oc- 

 curring during the division process. Cf. Dobell ('14) and Hart- 

 mann ('14) in re Amoeba lacertae; Nagler ('09), Glaser ('12) 

 and Wilson ('16) on the presence of a centriole in amebas; etc. 

 The work of Schardinger ('99), Wherry ('13) and Wilson ('16) 

 on the nuclear stages of amebas was done with care, yet Wilson 

 ('16) still remains in doubt as to whether or not these investi- 

 gators all worked on the same species. 



3. Awerinzew ('04, '06) found that the nuclear changes in 

 Amoeba protens are similar to those in the heliozoan Actino- 

 sphaerium; there being thus greater correspondence in the nu- 

 clear changes between species belonging to .different orders than 

 there is between species in the same genus. Logically therefore 

 Actinosp/iaeriiim would have to be placed in the same genus with 

 Amoeba proteus. 



4. There is the great practical objection that in many of the 

 larger species it is extremely difficult to find suitable division 

 stages even though thousands of individuals are at hand, and the 

 search is continued for days and weeks by an experienced in- 

 vestigator (Dobell, '10). Experimental work, which is usually 

 done with one of the larger species, would thus be greatly handi- 

 capped because of the great difficulty in determining the nature 

 of the organism employed. 



From these considerations it appears that the attempt to classify 

 the amebas on the basis of the nuclear changes is highly artificial 

 and exceptional, and if we may judge from past attempts to 

 classify organisms on the basis of a single character, is fore- 

 doomed to failure. This conclusion does not apply, however, to 

 very minute amebas in which no specific cytoplasmic characters 

 have yet been established, chiefly because of their very minute- 



