REPORT ON THE RADIOLARIA. 13 



Subgenus 1. Procyttarium, Haeekel, 1879. 



Procyttarium, Haeekel, Natiirl. Schopfungsgeschichte, ed. vii. p. 705. 



Definition. Central capsule spherical. 



1. Actissa princeps, n. sp. (PI. 1, fig. 1). 



Central capsule spherical, colourless or a little reddish, transparent, with a thick double-edged 

 membrane. Nucleus central, spherical, one-third as broad as the central capsule, containing a 

 single, central, glossy nucleolus. Protoplasm finely granulated, without oil-globules, with numerous 

 clear spherical vacuoles of equal size and at equal distances; the superficial layer of protoplasm 

 (immediately below the membrane) radially striated (fig. 1). In some older specimens the nucleus 

 was divided into numerous small nuclei (fig. la), which by further division gave the nuclei of 

 the flagellated spores (fig. 16); each spore with a very thin lateral flagellum (fig. Ic). Jelly-like 

 calymma twice as broad as the enclosed capsule, without xanthellse or yellow cells, pierced by 

 innumerable, very thin and long, undivided pseudopodia, which arise from the sarcode-matrix on 

 the outside of the membrane (six to eight times longer than shown in fig. 1). 



Dimensions. Diameter of the central capsule O'l to 012, of the nucleus 0'03 to 0'04, of the jelly 

 calymma 0'2 to 0'3. 



Habitat. Indian Ocean, Ceylon, Belligemma, Haeekel, 1881 ; also in a preparation from Station 

 271, Central Pacific, surface. 



2 . Actissa primordialis, Haeekel. 



Thalasgolampe primordialis, R. Hertwig, 1879, Organismus der Radiolarien, p. 32, Taf. iii. fig. 5. 

 Procyttarium primordiale, Haeekel, 1879, Natiirl. Schb'pf., ed. vii. p. 705, Taf. xvi. fig. 1. 



Central capsule spherical, dim-yellowish, with a thin, simple-edged but compact membrane. 

 Nucleus large, central (about half as broad), with one or two dark nucleoli; on its side an excentric 

 oil-globule, nearly of the same size. Protoplasm between nucleus and membrane, in the younger 

 specimens finely granulated and radially striped ; in the older specimens with numerous hyaline 

 globules (vacuoles). Jelly-envelope or calymma very voluminous, ten to twelve tunes as broad as 

 the central capsule, structureless, containing numerous yellow bodies (xanthelbe ?), pierced by 

 very numerous simple pseudopodia. 



Dimensions. Diameter of the central capsule Oil to 018, of the nucleus 0'04 to 0'09, of the jelly- 

 like calymma 1/2 to 1/5. 



Habitat. Mediterranean, Messina, Hertwig, 1878, surface. 



3. Actissa prototy pus, n. sp. 



Central capsule spherical, red-coloured, with a thick, double-edged membrane. Nucleus central, 

 spherical, half as large as the radius of the capsule, containing a large number (forty to sixty) of small 



