58 



ZOOLOGY 



SECT. 



complex. The protoplasm is distinctly divided into a central mass, 

 the medulla or endosarc (B, med.), in which the vacuoles are small, 



pse! 



1.Raj>hidiof)hrys 



c.vcw 



2. Nude aria 



3.Claf-hrulina 



Fia. 41. Various forms of Heliozoa. Sa, the entire animal; Sb, the flagellula; c. rac. 

 contractUe vacuple ; gr. gelatinous investment; nu, nucleus psd. pseudopods; sk. siliceous 

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



and an outer layer, the cortex or ectosarc (cort.), in which they are 

 very large. There are numerous nuclei (nu.) and chromatophores 

 (chr.\ the latter coloured green by chlorophyll, the characteristic 

 pigment of green plants. 



