ON THE LIFE-HISTORY OF THE FOtlAMINIFEKA. 177 



Fig. 66. X 690. The inner chambers of this specimen. The micro- 

 sphere measm-es 11 fix 9 [jl. 



Fig. 7. X 170. A yomig specimen of the microspheric form. The 

 microsphere measures 10 /x. /. Foreign particles collected at the mouth of 

 the shell. 



Fig. 8, a and b. x 980. Sections of two nuclei. In 8a the nucleoli 

 are vacuolated. 



Fig. 9. X 690. A pair of nuclei, with nucleoli of diflFerent sizes. One 

 of the larger nucleoli is vacuolated. 



Fig. 10. X 307. A pair of nuclei with their opposed surfaces flat, as 

 though they had recently separated. 



Fig. 11. X 730. Three consecutive sections through a dividing nucleus. 



In (a) the two parts of the nucleus are united by a constricted band ; 

 the right-hand part is larger than the left. 



In (b) the left-hand part is larger than the right. 



In (c) the left-hand part alone is seen. 



Fig. 12. X 690. A section through three chambers, showing irregular 

 stained strands continuous with the substance of the nuclei. 



MegalosjAeric form. 



Fig. 13. X 170. Specimen with thirty-nine chambers. Megalosphere 

 85/Li X 80/x ; nucleus 98 fi x 43 /n. Picro- carmine. 



Fig. 14. X 1275. Section through the nucleus of a specimen with 

 thirty -two chambers. It measures 65 ^x 40^. A large vacuolated nucleo- 

 lus (18fix 14/i) lies in the middle. The other nucleoli vary in size up to 

 4/i. Picro-carmine, hsematoxylin. 



Fig. 15. X 700. Section of the nucleus of a specimen with twenty- 

 three chambers. It sends a process through a canal leading to another 

 chamber. The nucleoli are seen to be drawn out as the result of the 

 stress to which they are subjected. Picro-carmine, cosine, methylene- 

 blue. 



Fig. 16. X 700. Section of nucleus. The reticulum is here coarser 

 than in the nucleus shown in fig. 15. The nucleoli vary in size up to 2/i. 

 Flemming's fluid, safranin. 



Figs. 17-19. X 710. Nuclei in optical section. Many of the nucleoli 

 are compound. Picro-carmine. 



In fig. 18 a large nucleolus is represented, having a vacuole in the 

 centre, and its walls composed of bodies similar to the small simple 

 nucleoli which lie in the reticulum. Smaller compound masses are also 

 present. 



Fig. 20. X 460. Nucleus with many small vacuolated nucleoli. Op- 

 tical section. Picro-carmine. 



Fig. 21. X 690. Nucleus with thin-walled vacuolated nucleoli. Their 



