between divisions|20 days |8 days |6 days Multinuclearity |binucleate |binucleate |binucleate very | occasionally | frequent; | | | tetranucleate |rarely | | occasional | Nucleus, shape |biconcave disc, |biconcave disc, |ovoidal | never folded | frequently folded| size |40µ × 18µ 46µ × 12µ 40µ × 32µ General resistance| | | to same | | | conditions |slight |very great |greater than | | | _discoides_ Surface of | | | posterior end |free from debris |free from debris |carries debris Effect of | | | mechanical | | | stimuli |slightly |responsive |very responsive | responsive | | Food cups |small |large |often enormous Reaction to |readily eaten; |readily eaten; |eaten only occasionally; carmine | rejected in a |rejected in a | often | few minutes | few minutes | retained for hrs. Distribution |sporadic, small |very common |sporadic, frequently | numbers | | in large numbers are the different species of amebas so absolutely different, even to the smallest detail? Why are the apparent resemblances and similarities of their more generalized kinetic characters, such as the formation of pseudopods, of ectoplasm, of crystals, of contractile vacuoles, the general character of endoplasmic streaming, the formation of ectoplasmic ridges, and so forth, found, upon analysis, to resolve themselves into a large number of details which differ more strikingly, the corresponding characters of one from those of the other, than do the generalized characters of which they are composed? These questions apply, of course, to all other organisms as well as to amebas. Unfortunately, however, these questions are at present unanswerable for all organisms. But for the amebas, at least, the problem of form can be rid of some irrelevant matter which, in numerous instances in the past, has been assumed to be properly included.