THE FORAMINIFERA 51 



Schaudinn also has witnessed the capture and digestion of a 

 Copepod by Myxotheca (41, p. 25), and finds that Patellina and 

 Discorbina feed on Copepod nauplii and Infusoria as well as on 

 Diatoms (45, p. 182). The pseudopodia of Gromia and Poly- 

 stomella have been seen to exercise a paralysing effect on Infusoria 

 which come in contact with them (M. Schultze). 



The pseudopodia are exceedingly viscid. When an object which 

 serves as food is entangled it becomes surrounded by protoplasm, 

 and if it is large the strands of the reticulum between it and the 

 shell become thicker and more numerous, and the object is drawn 

 inwards. Whether digestion may occur in the extended protoplasm 

 or only after the food enters the shell is uncertain. 



Myxotlieca arenilega, Schaudinn. N, nucleus; t, the gelatinous test with embedded sand grains. 

 (After Schaudinn, 41.) 



Contractile vacuoles occur in some of the fresh -water forms 

 (Eugli/pha, Trinema, Cyphoderia, Microgromia, and Platoum), but they 

 have not been seen in any of the marine genera. 



The granular bodies which are scattered through the protoplasm 

 are of different kinds. Some are coloured, and confer a red, 

 yellow, or brown colour on the protoplasm when seen in bulk. 

 These are allied in composition to the colouring matter of diatoms 

 (diatomin), and are probably derived directly from the food. Some 

 are fatty ; others, apparently proteid in nature, are stained by 

 picrocarmine, and are probably formed in the ascending metabolism 

 of the food. In OrUtolites comphnata starch grains are abundant, 

 but their formation is probably dependent on the presence of the 

 parasitic algae (zooxanthellae) which abound in the protoplasm in 

 this species. These algae also live in the pelagic Globigerinae. 



