494 LORANDE LOSS WOODRUFF AND RH, ERDMANN 



phase of the process which we term endomixis, it is obvious 

 that the phenomenon would still fall under endomixis and not 

 under parthenogenesis since the latter term is, according to our 

 interpretation, restricted to cases in which gametes undergo 

 Entwicklungserregung. The only way to justify the applica- 

 tion of the term parthenogenesis is sensu stricto to the phe- 

 nomenon which we call endomixis would be by proving that in 

 the latter process a reduction of the number of chromosomes 

 actually takes place in a micronucleus which can be considered 

 as the equivalent of a gamete, and that for this reduction there 

 is a compensation. 



However, if one is inclined to employ the term parthenogenesis 

 in a very broad sense to include all cases of Entwicklerregung 

 without regard either to the character of the cell (egg, gameto- 

 cyte, gamont, somatic cell) in which they occur, or to haploid 

 or diploid condition of the chromosomes, then endomixis is a 

 new type of parthenogenesis. It is always difficult to relate 

 properly a newly discovered phenomenon to analogous processes. 

 In the present instance this is doubly difficult owing to the fact 

 that in the protista the formation of a typical macrogamete 

 closely analogous with that of metazoa and metaphyta is the 

 exception rather than the rule. It is probable that future study 

 of other Protista (e.g., bacteria, amoeba, trypanosomes, Plas- 

 modia, etc.) will reveal nuclear reorganization processes which 

 will make certain the proper place of endomixis among the already 

 complicated apocaryomictic phenomena. 



X. ENDOMIXIS AND ITS RELATIONS TO VARIATION, HEREDITY 

 AND THE SIGNIFICANCE OF CONJUGATION 



We deem it inadvisable in the present paper — which is essen- 

 tially a description of cytological and physiological observations 

 — to enter into an extended discussion of the wide theoretical 

 bearings of endomixis on the problems of variation, heredity and 

 amphimixis. It is important, however, to consider briefly certain 

 points which are obviously suggested by the observations de- 

 scribed. This may be facilitated by a rapid survey of the facts 

 which are to be interpreted. 



