EEPORT ON THE RADIOLAEIA. 513 



12. Stylodictya hertwigii, Haeekel. 



Shjlospira ararlmia, R Ilertwig, 1879, Organiamus d. Eadiol., p. 59, Taf. vi. fig. 8. 



AU rings of the disk convoluted in a simple regular spiral, with increasing breadth from the 

 centre ; the fifth ring twice as broad as the second. Pores regular, circular, two on the breadth of 

 each ring. Twelve piercing radial beams and some others interrupted, prolonged into twelve to 

 twenty radial marginal spines, bristle-shaped, about as long as the diameter of the disk. 



Dimensions. — Diameter of the disk (with five rings) 0-15 ; breadth of the second ring O'Ol, of 

 the fifth 0-02 ; pores O'OOG. 



Habitat. — Mediterranean (Messina), E. Hertwig. 



13. Stylodicyta dujardinii, Haeekel. 



Stijlospira dujardinii, Haeekel, 1862, Monogr. d. EaJiol., p. 51.5, Taf. x.xix. fig.s. 9, 10. 



All rings of the disk convoluted in a sunple regular spiral, of nearly equal breadth. Pores 

 regular, circular, two on the breadth of each ring. Very numerous (twenty to thirty or more) 

 piercing radial beams, ijrolonged into Ijristle-shaped marginal spines, about as long as the diameter 

 of the disk. 



Dimensions. — Diameter of the disk (with six rings) U'12 ; breadth of each ring U'Ol ; 

 pores 0-004. 



ITaMtai. — Mediterranean (Messina), Haeekel. 



14. Stylodictya echinastrum, Ehrenberg. 



Stijlodictya echinastrum, Elirenberg, 1876, Abhandl. d. k. Akad. d. Wis.s. Berlin, p. 84, 

 Taf. xxiii. fig. 1. 



All rings of the disk convoluted in a double spiral, of nearly equal breadth. Pores irregular, 

 roundish, two to three on the breadth of each ring. Marginal spines numerous, twenty to thirty, of 

 very different size, the largest conical, strong, about as long as the diameter of the disk, and on the 

 base as broad as one ring. 



Dimensions. — Diameter of tlie dislc (with five rings) 0'12 ; breadth of each ring O'Ol ; pores 

 0-002 to 0-006. 



Habitat. — Fossil in the rocks of Barbados. 



15. Stylodictya clavata, Ehreuberg. 



Stylodictya clavata, Ehrenberg, 1875, Abhandl. d. k. Akad. d. "Wiss. Berlin, p. Si, Taf. xxiii. 

 fig. 2. 



All rings of the disk convoluted in a half spiral, of nearly equal breadth ; each ring by four 

 zigzag beams (crossed in two perpendicular diameters) divided into four equal quarters; the spual 

 line of each quarter rmg halving both neighbouring quarters. Pores regular, circular, two on the 

 breadth of each ruig. Eight marginal spines short, conical, with thin pedicle ; four perradial (as 



(ZOOL. CHALL. EXP. PART XL. — 1885.) Er 65 



