REPORT ON THE RADIOLARIA. 525 



Dimensions. Eaclius of each arm (length from the centre to the distal end) 013; breadth of the 

 truncated end 01. 



Habitat. Tropical Pacific, Philippine Sea, Station 200, depth 250 fathoms. 



2. Dictyastrum bandaicum, Haeckel. 



Rhopalastrum landaicum, Harting, 1863, Mikr. Fauna Banda-Zee, p. 16, Taf. iii. fig. 45. 



Arms nearly square, with convex edges, in the middle a little broader than at both ends, about 

 half the diameter of the central disk. Differs from the nearly allied preceding species by the 

 half size of the arms and the convex edges. 



Dimensions. Radius of each arm 012, its greatest breadth 0'07. 



Habitat. Tropical Pacific, Banda Sea, Harting. 



3. Dictyastrum hexagonum, n. sp. (PL 43, fig. 7). 



Rhopalastrum hexagonum, Haeckel, 1880, Atlas (pi. xliii. fig. 1). 



Arms nearly triangular, one and a third times as broad at the distal end as long, and three 

 times as broad as at the base. Central disk about the same diameter. In each arm six simple 

 broad chambers. If we connect the six corners of the truncated distal ends by straight lines, we 

 get a regular hexagon. 



Dimensions. Radius of each arm 017, basal breadth 0'06, terminal breadth 017. 



Habitat. Equatorial Atlantic, Station 347, surface. 



4. Dictyastrum trirrhopalum, n. sp. 



Arms club-shaped, five times as long as broad at the base, at the thickened end three times 

 as broad as at the base. Diameter of the central disk equals half the length of the arms. 

 (Similar to Rhopalastrum malleus, PI. 43, fig. 1, but with three equal angles and much smaller disk.) 



Dimensions. Radius of each arm - 25, basal breadth 0'04, distal breadth 012. 



Habitat. Pacific, central area, Station 273, surface. 



Subgenus 2. Dictyastromma, Haeckel. 

 Definition. Arms on the distal end provided with terminal spines. 



5. Dictyastrum trispinosum, n. sp. (PL 43, fig. 5). 



Rliopalastmm trispinosum, Haeckel, 1881, Prodromus et Atlas (pi. xliii. fig. 5). 



Arms trapezoid, at the rounded distal end twice as broad as at the base, with a strong and 

 short, conical, terminal spine. Diameter of the circular central disk about equal to the length and 

 the greatest breadth of the arms. 



Dimensions. Radius of each ami 015, basal breadth 0'06, distal breadth Oil. 



Habitat. Equatorial Atlantic, Station 347, surface. 



