PROTOZOA 



31 



here some individuals may produce spores which are all alike, 

 isopores, while others produce two kinds of spores, large, macro- 

 spores, and small, microspores. These spores are all flagellate, 

 each having a single flagellum. 



FlG. 11. Lichnaspis giltochii,^. Radiolarian ; skeleton, a, a, a, a, northern polar spines; 

 b, b, b, b, northern tropical spines; c, c, c, -, equatorial spines; d, d, </, d, southern tropical 

 spines; e, e, e, -, southern polar spines. (After Haeckel, from Calkins' Protozoa.) 



The Radiolaria usually float near the surface of the ocean, 

 but they may sink to greater depths. They constitute the larg- 



