SI"X IN PROIOZOA 175 



cjucnr under poor cultural conditions and in warmer weather. In 

 "copulation," two individuals first underwent plasuioganiy; then the 

 contents of one shell flowed into the other. The chroniidial material 

 of the two then mingled, hut karyogamy was not observed. Encyst- 

 ment followed, but before encystment "chromidia" emerged from 

 the nuclei, most of which degenerated. This process occurred regu- 

 larly in late w inter. "Conjugation" was similar to "copulation" except 

 that three individuals were involved. In time, new secondary nuclei 

 were said to form from the chromidia in the cyst. 



A few other genera of the Difflugiidae are represented in the 

 records of "copulation" and "conjugation" for example, Ceiitropyxis 

 iiculcata for which Rhumbler (1895) reported "conjugation" with- 

 out karyogamy, and Schaudinn (1903) reported "copulation" fol- 

 lowed by encystment. 



"Copulation" and "conjugation" have also been recorded for 

 species of Eiiglypha and its relatives. Blochmann (1887) isolated a 

 pair of Eiiglypha aheolata. Tw^o days later the contents of these two 

 had combined to form a third and larger shell. Reukauf (1912) made 

 a similar observation for the same species, but encystment followed, 

 as it did after "copulation" in an unnamed species described by 

 x\werinzew^ (1906) and in Eiiglypha sciitigera by Penard (1938) 

 (Fig. N, 7 to 11). These independent observations agree so well as 

 to details that complete cell fusion seems to be indicated. 



Other species in the Euglyphidae for which "copulation" or 

 "conjugation" has been reported are Cyphoderia (Rhumbler, 1895; 

 Cash, Wailes, and Hopkinson, 1915); Trinevm lineare (Penard, 

 1902); Nebela collaris (Cash and Hopkinson, 1905); Nehela and 

 Assuliva (Awerinzew% 1906); Trbieiim eiichelys (Cash, Wailes, and 

 Hopkinson, 1915). 



Although the above-cited records show that cytoplasmic fusion 

 is a common phenomenon among the Testacea and that complete 

 fusion of two cells including karyogamy may take place, in no case 

 has there been a demonstration of haploid-diploid sequences. 



Order Foraminijera 



Early students of the Foraminifera noted that in many of the 

 polythalamous species there were two types of shells: one with a 

 larger first chamber, or prolocujum, designated megalospheric, and 



