THE FORAMINIFERA 



characters of Saccammina sphaerica (Fig. 17, b). He found that 

 among the 286 specimens which he examined, a single nucleus 

 was present in all but one 

 (which had two nuclei, and 

 was regarded as abnormal), 

 and the phases presented by 

 the nuclei fell into a con- 

 tinuous series. They corre- 

 spond with those of the nucleus 

 of the megalospheric form of 

 Polystomella. The nucleus in- 

 creases in size with the growth 

 of the organism, and the 

 nucleoli ("binnen korper"), at 

 first large and few, increase 

 in number and diminish in 

 size. Finally (PI. 23, Fig. 67) 

 the nuclear membrane breaks, 

 and linin threads containing 

 chromatin grains are dispersed 

 in the protoplasm. From these 



FIG. 17. 



a, Astrorhiza limicola, Sandahl., x 6. b, Saccammina sphaerica, M. Sars, x!2. c, Pilidina 

 je/reysii, Carpr., x 12. d, Hyperammina subnodosa, Br., x 7. In a, b, andrf the test lias been 

 laid open. (From Brady, "Challenger" Report.) 



later nuclear phases it appeared that some process of reproduction 

 was imminent, but none was observed. The formation of zoospores 

 by the Foraminifera was at that time unrecognised, and Rhumbler 



