RADIOLARIA 373 



Genus Hexacontium (Fig. 170, a) 



Central capsule and skeleton elliptical or cylindrical 



Family 2 Prunoidae 



Genus Pipetta (Fig. 170, 6) 



Central capsule and skeleton discoidal or lenticular 



Family 3 Discoidae 



Genus Staurocyclia (Fig. 170, c) 

 Similar to the above, but flattened Family 4 Larcoidae 



Fig. 170. a, Hexacontium asleracanthion, Xl30; b, Pipetta tuha, 

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

 XlOO; e, Sphaerozoum ovodimare, X30 (Haeckel from Kiihn). 



Genus Cenolarus (Fig. 170, d) 



Colonial; individuals with anastomosing extracapsular cytoplasm, em- 

 bedded in a jelly mass Legion 3 Polycyttaria 



Without latticed skeleton, but with siliceous spicules arranged 

 tangentially to central capsule Family 1 Sphaerozoidae 



Genus Sphaerozoum (Fig. 170, e) 



Central capsule of each individual enclosed in a latticed skeleton . . 

 Family 2 Collosphaeridae 



Genus Collosphaera 



Suborder 3 Monopylea Hertwig 



Without any skeleton Legion 1 Nassoidea 



Family 1 Nassoidae 



Genus Cystidium (Fig. 171, a) 



With skeleton 



Without a complete latticed skeleton Legion 2 Plectellaria 



Skeleton a basal tripod Family 1 Plectoidae 



