422 PROTOZOOLOGY 



Genus Thalassophysa 



Fig. 196 a, Lampoxanthium pandora, X20 (Haeckel); b, Thalassicolla 

 nucleata, Xl5 (Huth). 



Nuclear wall crenate 



Huge double spicule Family 4 Thalassothamnidae 



Genus Thalassothamnus 



A latticed skeleton, with branching and thorny spines 



Family 5 Orosphaeridae 



Genus Orosphaera 



Solitary, skeleton complex, often concentric 



Central capsule and skeleton spherical Family 6 Sphaeroidae 



Genus Hexacontium (Fig. 197, a) 



Central capsule and skeleton elliptical or cylindrical 



Family 7 Prunoidae 



Fig. 197. a, Hexacontium aster acanthion, Xl30; b, Pipetta tuba, XlOO; 

 c, Staurocyclia phacostaurus, Xl30; d, Cenolarus primordialis, XlOO; 

 e, Sphaerozoum ovodimare, X30 (Haeckel). 



