RADIOLARIA 



425 



Genus ChaUengeron (Fig. 200, a) 



Skeleton smooth or with small spines Family 7 Medusettidae 



Genus Medusetta (Fig. 200, b) 



One skeleton; spherical or polyhedral, with an opening and with radiat- 

 ing spines 

 Skeleton spherical or polyhedral, with uniformly large round pores 

 Family 8 Castanellidae 



Fig. 200. a, ChaUengeron mjvillei, Xl05 (Haeckel); b, Medusetta ansata, 

 X230 (Borgert); c, Castanidiimi murrayi, X25 (Haecker); d, Circoporus 

 octahedrus, X65 (Haeckel); e, Tuscarora murrayi, X7 (Haeckel); i,Coelo- 

 dendrum ramosissimum, XlO (Haecker). 



•Genus Castanidium (Fig. 200, c) 



Skeleton similar to the last, but the base of each radial spine sur- 

 rounded by pores Family 9 Circoporidae 



Genus Circoporus (Fig. 200, d) 



Skeleton flask-shaped with 1-2 groups of spines 



Family 10 Tuscaroridae 



Genus Tuscarora (Fig. 200, e) 



Central portion of skeleton consists of 2 valves 



Valves thin, each with a conical process which divides into branched 

 tubes Family 11 Coelodendridae 



Genus Coelodendrum (Fig. 200, /) 



