SPECIAL MORPHOLOGY AND TAXONOMY OF SARCODINA 333 



rise to the pseudopodial network which acts as a trap for the capture 

 of diatoms, cnistacea, rotifers and other smaller objects used as food. 

 In the perforate t\pes pseudopodia are also protruded through the 

 finer pores (foramina) of the shell. 



One large ^'esicular nucleus is characteristic of both single and 

 many-chambered types. In the latter the nucleus may be confined 

 to the first formed, or inner, chambers, although it may wander 

 throughout the entire organism. In many cases it is replaced by 



Fig. 149. — Diagram to show the mode of origin of the Nodosarine type of Foramini- 



fera shell. 



several nuclei, and there is a general tendency throughout the group 

 to form chromidia by multiple division, or fragmentation of the 

 primary nuclei. 



Reproduction may or may not be accompanied by fertilization 

 phenomena and throughout the group there is a more or less regular 

 alternation of sexual and asexual processes, accompanied in many 

 cases, by morphological evidence of sexual or asexual generation. 

 In its simplest case, asexual reproduction consists of so-called bud- 

 ding division. In Alloc/ronna for example, the protoplasm streams 



