Chromosomes play so important a role in heredity & development that it is desirable to know their entire life cycle since this knowledge will provide a basis for better understanding of their behavior. Contents of this study: Introduction, The genus "Holomastigotoides", Species of "Holomastigotoides" in "Prorhinotermes", "Holomastigotoides tusitala" species novum, "Holomastigotoides diversa" species novum, Centrioles & achromatic figure, Relation of chromosomes to nucleoli, Relation of chromosomes to nuclear membrane, Single chromatids, Double chromatids, Discussion, Summary, & References. 35 plates. This is a print on demand edition of an important, hard-to-find publication.