48 



ANIMAL BIOLOGY 



ous species of Amoeba, such as those comprising the genus End- 

 amoeba, live within the bodies of Man and other animals. Fur- 



Mouth of shell 



Fig. 19. — A, Arcella showing the protoplasm through the transparent shell 

 and also protruding as pseudopodia; B, Difllugia showing the same. 



thermore, there are many com- 

 mon fresh-water genera, such as 

 Arcella and Difllugia, that have 

 resistant protective coverings, 

 or shells. The shells have an 

 opening through which the 

 pseudopodia are protruded so 

 that locomotion, securing of 

 food, etc., can be performed. 

 But all of these animals, whether 

 free-living or parasitic, naked 

 or provided with a shell, are 

 creeping cells with more or less 

 broad or blunt finger-form pseu- 

 dopodia and comprise the first 

 order of the Sarcodina known 

 as the Amoebae a. (Figs. 6, 11, 

 19, 245.) 



An immense group of chiefly 

 marine Protozoa, the Forami- 

 nifera, constitutes the second 

 order of the Sarcodina. Most 

 species have quite complex 

 shells of calcium carbonate, with Fig. 20. — Allogromia, one of the 

 one or many openings through few fresh-water Foraminifera. Note 



l- -i j l • i i- the pseudopodial mass emerging from, 



which delicate pseudopodia and surroun ding the shell. (Modified, 

 emerge, branch, and flow to- after Cambridge Natural History.) 



Food 



Pseudopodia 



