THE SARCODINA 



75 



spindles, or blade-shaped plates, and may become firmly attached 

 to one another, forming latticed skeletons, like those of Radiolaria 

 (Clathrulina, Fig. 39). Intermediate stages are seen in such forms 

 as DiplocysttS) where the plates are very small and arranged without 



Fig. 39. Clathrulina elegans Cienk. [GREEFF.] 



any apparent order in the gelatinous mantle. In Raphidiophrys 

 (Fig. 40) the silicious plates are much larger and more regularly 

 arranged, while in Pinaciophora and Acanthocystis (B, C, D) they be- 

 come so closely knit that they form an efficient shield. In Acantho- 

 cystis, each plate is a small rectangular prism, laid tangential to the 

 surface with sharper spicules arranged at intervals at right angles to 



