CLASS RHIZOPODA. 



FIG 



Arcel'la den t-l'ta. 

 Crown Amoeba. 



Pseudopodia (p). 

 (Greatly enlarged.) 



FIG. 4. 



as it is called, is the ordinary method whereby the Amcebse 

 are multiplied.* 



Figure 8 represents an Amoeba-like Rhizopod, which is 

 found in great abundance in mossy pools. 

 It will be observed to have a regularly 

 formed shell, or covering, into which it is 

 able to withdraw. 



The Foramiiiifera proper are marine, be- 

 ing; found in great abundance on the high Projecting from the 



shell are several 



seas, where their dead shells fall to the bot- 

 tom in a continual shower and form 'there, in 

 time, a deposit of great thickness, which, as it hardens, be- 



comes limestone. Thus, though each one 

 is almost infinitely small, these animals, 

 working from earliest ages, have been 

 active agents in molding and modifying 

 the geological formation of the globe, f 



Globigerina (glob ij er I'na) is the most 

 abundant form, its dead shells character- 

 izing the ooze that covers the ocean 

 depths. On quiet evenings, the live ani- 

 mals may be skimmed from the surface 

 of the water, though it is quite difficult 

 to secure specimens which have not been mutilated, as 

 the long calcareous (kal ka're us) FlG 5 



spines are very brittle. 



* When the surroundings of the ani- 

 mal are unfavorable for reproduction by fis- 

 sion, budding may take place. In this case, 

 the new Rhizopod, in some species, remains 

 attached to the shell of the parent, giving 

 rise to the forms known as Nummulites, etc. 



t Foraminifers (fo ra mm'ifers) have fur- 

 nished in large part the extensive chalk-cliffs 

 of England, and much of the architectural material of the world, as well as that 

 of the marl-beds, so abundant on the Atlantic coast of the United States. 



Globigerl'na bul loi'des. 

 (Greatly enlarged.) 



Num mu tt'tes a tn'i ca. Rhizopod. 



