r 



PROTOZOA 17 



kuhnia (Fig. 12), an aUied form, the pseudopodia anastomose 

 to a great extent and form a close reticulum. 



Fig. 12. — LieberkiAnia, with 

 reticulate pseudopodia. 



Class V. Heliozoa. 



Mostly spherical in form, sometimes supported by a siliceous 

 skeleton, and with radiating stiff pseudopodia. The protoplasm 

 of the body is very vacuolated, and contains one or more nuclei. 

 Near the surface of the body one or more contractile vacuoles 

 may be observed. With few exceptions, they inhabit fresh 

 water. 



Actinophri/s sol, the sun animalcule (Fig. 13), is one of the 

 common microscopic objects found in still fresh water. It may 

 be met with floating amongst the leaves of submerged plants, 

 and presents a globular body which undergoes slight changes of 

 outline, and is usually very vacuolated. The single nucleus 

 occupies a central position, the contractile vacuole is on the 

 surface, and food vacuoles containing portions of algae, infusoria, 

 etc., may be seen throughout the body. The pseudopodia are 

 stiff and hair-like, and are supported by an axial fibre ; they 

 can be withdrawn into the body. When they come in con- 

 tact with a particle of food they bend slowly over it, and bring 

 it near to the surface of the protoplasmic body, when it is 

 swallowed with the surrounding drop of water, and thus a food 



2 



