60 



ZOOLOGY 



SECT. 



(Fig. 42, 2, #.), in other cases it is surrounded by a capsule of loosely 

 woven fibres through which the pseudopods pass, thus reminding 

 us of the state of things characteristic of perforate Foraminifera. 



c.vac 



S.Nuclearia 



3.Cla>hmlina 



FlQ. 42. Various forms of Heliozoa. 3a, the entire animal ; 3b, the flagellula ; c. rar. 

 contractile vacuole ; g. gelatinous investment; nu. nucleus; psd. pseudopods; ,vA\ 

 siliceous skeleton ; sp. spicules. (From Biitschli's Protozoa, after Schulze and Greeff.) 



One genus has a shell formed of agglutinated sand-grains ; in 

 another (Fig. 42, 1) the skeleton consists of loosely matted needles 

 of silica. Lastly, in the graceful Claihrulina (3) the body is 



