REPORT ON THE RADIOLARIA. 447 



8. Heliodiscus polymorphus, n. sp. (PI. 34, figs. 11, 12). 



Disk with smooth surface, four times as broad as the medullary shell. Pores irregular, roundish ; 



ten to twelve on the radius. Marginal spines ten to fifteen, i^yramidal, angular, very irregular and 

 variable in size and distribution, the largest nearly as long as the diameter of the disk, as broad at 

 the base as the radius of the medullary shell. 



Dimensions. — Diameter of the disk 015 to 0'2, of the medullary shell 0-04 to 0'05 ; length of 

 the radial spines 0-06 to 018, basal breadth 0-02 to O'OS. 



Habitat. — Central Pacific, Stations 265 to 268, depths 2700 to 2900 fathoms. 



9. Heliodiscus solaster, u. sp. (PI. 34, fig. 4). 



Disk witli smooth surface, three times as broad as the medullary shell. Pores subregular; 

 roundish ; nine to ten on the radius. Marginal spines fifty to sixty, cylindro-conical, flexuose, very 

 variable in size, the largest nearly as long as the diameter of the disk. The spines lie not only in 

 the equatorial plane (as usual), but also in two to four crowded girdles on both sides of it. 



Dimensions. — Diameter of the disk 015, of the medullary shell 0'05 ; length of the radial 

 spines 0-05 to 015, basal breadth Q-QOS. 



Habitat. — Indian Ocean, Madagascar, Rabbe, surface. 



Subgenus 2. Heliodiscilla, Haeckel. 



Definition. — Surface of the disk covered with radial spines. Bases of the marginal 

 spines free, without a connecting equatorial girdle. 



10. Heliodiscus jjhacodiscus, Haeckel. 



Heliodiscus phaaodiscus, Haeckel, 1862, Monogr. d. Eadiol., p. 437, Taf. xvii. ligs. 5-7. 

 Haliomma phacodiseus, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 815. 



Disk with spiny surface, three times as broad as the medullary shell. Pores regular, circular ; 

 six to eight on the radius. Marginal spines twelve to sixteen, conical, as long as the radius of the 

 disk, and one-third as broad as the diameter of the medullary shell. 



Dimensions. — Diameter of the disk 012 to 016, of the medullary sheU 0'04 to 0'05 ; length of 

 the marginal spines 0'06 to 0'08, basal breadth O^Ol to 0"02. 



Habitat. — Mediterranean (Messina), Canary Islands (Lanzerote). 



11. Heliodiscus amphidiscus, Haeckel. 



■Heliodiscus amphidiscus, Haeckel, 1862, Monogr. d. Eadiol., p. 437. 



Haliomma amphidiscus, J. Miiller, 1858, Abhandl. d. k. iVkad. J. Wiss. Berlin, p. 154, 

 Taf. ii. figs. 3-7. 



Disk with spiny surface, three times as broad as the medullary shell. Pores regular, circular ; 

 eight to ten on the radius. Marginal spines twelve to fifteen, l)ristle-shaped, not larger than the 

 surface spines, about as long as the radius of the medullary shell. 



