30 



AMCEBA, VOKTICELLA, PAKAMECIUM 



One great group, or order, called Foraininifera, are nearly 

 all marine. The shells of these animals, in most species 

 composed of Ume carbonate, have either one or two large 

 terminal openings or are perforated with many minute 

 openings. Through these minute holes there pi-oject long, 



delicate protoplasmic thi'eads, the 

 pseudopodia. These fine pseudo- 

 podia often unite to form a net- 

 work about the shell (Fig. 10). 

 The sliells of man}' Foraminifei-a 

 are rather complicated in struc- 

 tvue and present a variety of 

 shapes and patterns. Many of 

 them are divided into chambers. 

 Nevertheless, the)' are one-celled 

 animals, because all the chambers 

 are connected ^\•itll one another 

 so that the protoplasm consti- 

 tutes one body mass, or cell. 

 The marine Pi'otozoa are myriad m number of individuals. 

 One species especialh', called Glojngeiiiia, lives in such 

 immense numbers in the sea, usually near the surface of the 

 water, that the dead shells, which are constantly falling 

 downward, form a mud, or ooze, in some cases of consider- 

 able thickness, on the bottom of the ocean. The shells of 

 this animal are microscopic in size, and composed of lime 

 carbonate. In England and France, great betls of white 

 chalk exist to-flay which, when examined under a mi- 

 croscope, prove to be composed almost wholly of the shells 

 of globigerina and other minute Foraminifera. 



Slipper animalcule, or Paramecium. — Unlil^o the amoeba, 

 this protozoan has a definite shape. II is microscopic, but 



Fig. 10. — One of the J'^orami- 

 nifera with streams of proto- 

 plasm (pseudopodia) i^rojeet- 

 ing ttiroiigh openings in the 

 sliell. After Scliultze. 



