THE ORGANIZATION OF THE PROTOZOA 



35 



in the case of Difflugia the foreign particles used are taken up by the 

 pseudopodia during the process of being retracted ; the surface of 

 the pseudopodium then becomes wrinkled, and particles of debris 

 are caught in these wrinkles, and so drawn into the interior of the 

 protoplasmic body, in which they are stored up in the fundus of 

 the shell, like the plates in Euglypha, and are utilized in the growth 

 of the shell, or in repairing damages to it, or in building a new shell 

 when the animal reproduces itself by division. 



FIG. 17. Haliphysema iumanowiczii, a foraminifer which builds up its house out 

 of sponge-spicules. A, part of the protoplasm stained to show the nuclei (n.) ; 

 B, a living specimen with expanded pseudopodia (p.). After Lankester (11). 



The simplest architectural type of shell or test is a simple spherical or 

 oval capsule, usually with a large aperture at one pole through which the 

 protoplasm is able to creep out in order to capture food or perform the function 

 of locomotion (Fig. 16). The wall of the test may be imperforate, or may 

 have fine pores through which also the protoplasm can stream out. With 

 continued growth of the organism, the original shell may become too small 

 for its requirements. Then the organism may reproduce itself by fission. 



