24 



THE FOEAMINIFEEA 



podia, and only those fragments that possessed a 

 nucleus ^vere able to secrete fresh material to repair 

 the broken shell. The outer surface of the nucleus, 

 and even the nucleoli, are often covered with fine 

 strands of chromatin forming a reticulum. 



The nucleoli (fig. 14) appear to be the active 

 portion of the nucleus in effecting the reproduction 

 from an old nucleus by the formation of a morula- 



5 6 7 8 



Fig. 15. — The Successive Stages in the Division of the Nucleus 

 IN Calcituba polyjiorpha. After Schaiidinn and Sclilnmherger. 



like centre within the nucleus. An interesting series 

 of stages in the reproduction of nuclei in this way 

 has been described by Schaudinn in Calcituba 

 ]pohjmorj)Ua, a Foraminifer from the Adriatic Sea 

 (fig. 15). He shows that the nucleus, surrounded by 

 protoplasm, is invaded by the latter, which breaks up 

 into globules, penetrating little by little into the 

 nucleus. The protoplasm disintegrates the chromatin 



