Ko. 646] SHORTER ARTICLES AND DISCUSSION 467 



in whicli there is a union of a sperm and an eg^. This hitter 

 process is fundamental in the life of at least all the higher 

 Metazoa. By this union the race is perpetuated and liercditary 

 characters are intermingled. It would seem that stndies of a 

 similar process in the unicellular forms might tln-ow liglit upon 

 the basic relations of the sexual process to tlie life of proto- 

 plasm. 



Various investigators have slnnvn tliat eonjngation is a rela- 



such as the Paramecium, and that hereditary cliaraeters are 

 intermingled in this way. During conjugation two Paraniecia 

 fuse by their oral surfaces and there is an interchange of nu- 

 clear material between the individuals. Tlie latter tlien sepa- 

 rate and reproduction by division occurs. The races resulting 

 from such divisions show the effects of modifications due to 

 hereditary characters coming from both the conjugating indi- 



In the case of the more primitive Protozoa, the Anueba and 

 other Rhizopods, not a great deal is known. It has been ob- 



whether or not true conjugation occurs with ititercliange of 

 nuclear material and subsequent modification of the otl'^prinir. 

 If such proves to be the case, we shall have shown that ih-' phe- 

 nomena of sex are found in the very lowest aiiiina!>. ami aiv of 

 general fundamental importance in the life i)r()('('ss. 



The present investigation was undertaken in the effort to 

 throw some light on this question. An attempt was made to 

 test the matter by inducing conjugation between various indi- 

 vidual Rhizopods and noting if any inherited differences arose 

 from these unions. (A cytological study of the behavior of 

 the nuclei of such individuals must be made before the evidence 

 can be fully weighed.) A shelled Rhizopod, Difjlugi-a corona, 

 was used, since the shell exhibits marked characteristics which 

 vary among the different races of the species. The ordinary 

 shellless Amti'ba i)resents so few cliaraeters oi a i)ennanent na- 

 ture that it is unsuited for a study such as this. The Dif- 



legs represcnTi'il l.y ^-pui.'^ {M-c.ici'tinu- fmin tin- rMund.'.I aiioral 

 surface. The animal lives inside this sh.'ll and tlii'usts its 

 pseudopodia from the oral oix-niug. ft reproduces by division, 

 as other Protozoa, half the body being extruded from the oral 



