132 BRUCE D. REYXOLDS. 



shown contrasted with a normal individual in Fig. 4. (See 

 Reynolds '23.) 



As can readily be seen, the morphological differences between 

 this abnormal specimen and a normal individual were quite 

 marked; consequently they could be kept in the same concavity 

 without any danger of confusion. The abnormal form could be 

 reared, and it was found to breed true to type. By January 12 

 34 generations had been obtained from the abnormal Arcella, 

 while the normal individuals of the line from which it sprung had 

 given rise to 37 generations. During this time, a period of 52 

 days, the normal and abnormal organisms had been kept in 

 different receptacles, and no exchange of medium between them 

 had been made. In accordance with other findings, therefore, 

 they should have reacted negatively towards each other's frag- 

 ments of protoplasm even though both had possessed the same 

 morphological characteristics. In testing this out on January 12 

 it was found that they exhibited a violent shattering reaction. 

 On the same day an abnormal specimen Ab-34 was P u t m the 

 same concavity with a normal organism qd-123, both of which 

 belonged to the same line (qd) of clone Q. By making daily 

 tests " it was found that the interactions continued to be negative 

 for three days. From the fourth day on, cross-fusion took place 

 between them readily. 



Another experiment involving the abnormal form was also 

 started on January 12. In this case a normal individual j-i85, 

 which was descended from a specimen taken from a wild culture 

 on June 26, IQ22, 2 was placed in a concavity with an abnormal 

 organism Ab~34, after it had been demonstrated experimentally 

 that one would not fuse with fragments of the other's protoplasm. 

 Then the usual procedure of daily testing the interactions be- 

 tween the progeny of these two organisms was carefully practiced. 

 During the first five days the involved protoplasms were shat- 



1 In this and the following experiment all amputations, and subsequent obser- 

 vations of protoplasmic reactions, were made without removing the organisms from 

 their containers. 



2 While the two organisms used in this experiment belonged to the same species, 

 and probably at some time in the past had a common ancestor (since their progeni- 

 tors were isolated from the same wild culture); their relationship was certainly re- 

 mote, for the two clones to which they belonged had been under observation for 

 nearly seven months. 



