REPORT ON THE RADIOLARIA. 679 



2. Tholonium ellipticum, n. sp. 



Outer shell ellipsoidal, without dome-shaped protuberances, with smooth surface, without 

 radial spines ; network delicate, with subregular, circular pores. Inner shell with regular, circular, 

 hexagonally framed pores, twice as broad as the bars ; ten to twelve pores on the semicircle of 

 one cupola. 



Dimensions. Major axis of the outer shell 016, minor axis 014 ; major axis of the inner 

 shell 014, minor axis 012 ; pores O'OOS, bars 0'004. 



Habitat. Pacific, central area, Station 267, depth 2700 fathoms. 



3. Tholonium sphcericuin, n. sp. 



Outer shell spherical, without dome-shaped protuberances, with smooth surface, without radial 

 spines ; network very delicate, with very small subregular, circular pores. Inner shell with regular, 

 circular pores of the same breadth as the bars ; fourteen to sixteen on the basal semicircle of one 

 cupola. 



Dimensions. Diameter of the spherical outer shell 015, inner shell 012 ; pores and bars of 

 the inner shell O'OOS. 



Habitat. Indian Ocean, Zanzibar, Pullen, depth 2200 fathoms. 



Subgenus 2. Tholonilla, Haeckel. 

 Definition. Surface of the outer shell covered with radial spines or thorns. 



4. Tholonium hexonium, n. sp. (PI. 10, fig. 17). 



Outer shell ellipsoidal, without dome-shaped protuberances, covered with numerous (thirty to 

 fifty) thin and long, bristle-shaped radial spines ; network very delicate, irregular, with roundish 

 pores. Inner shell with six marked hemispherical domes of somewhat different sizes ; pores regular, 

 circular, with prominent hexagonal frames, twice as broad as the bars ; ten to twelve on the basal 

 semicircle of one cupola, 



Dimensions. Major axis of the outer shell 015, minor axis 014 ; major axis of the inner 

 shell 013, minor axis 012 ; pores O'OOS, bars 0'004. 



Habitat. Pacific, central area, Station 271, depth 2425 fathoms. 



5. Tholonium sphceronium, n. sp. 



Outer shell very thin walled, spherical, without dome-shaped protuberances, with smooth 

 surface, excepting eight large radial spines, rising from the eight corners of the inner cubical central 

 chamber. Pores of the outer shell very small, subcircular. Inner shell very thick walled, with six 

 marked hemispherical domes ; pores subregular, circular, with prominent hexagonal frames, twice 

 as broad as the bars ; six to eight on the semicircle of one cupola. 



