REPORT ON THE RADIOLARIA. 813 



B. Tribe II. C e r i a s p i d a, Haeckel. 



Definition. — D o r a t a s p i d a, the spherical shell of which is composed of twenty 

 perforated plates, produced by union of the branches of the two opposite apophyses, 

 which arise from each radial spine. Therefore the meshes of the shell are partly 

 sutural, partly parmal. 



Genus .351. Dorataspis,^ Haeckel, 1860, Monatsber. d. k. preuss. Akad. 



d. AViss. Berlin, p. 811. 



Definition. — D o r a t aspi d a with twenty plates, which are perforated by forty 

 aspinal pores (two pores in each plate). Surface of the shell without combs, dimples, 

 and by-spines. 



The genus Dorataspis opens the long series of the Ceriaspida, or of those 

 Dorataspida in which the shell is composed of twenty plates, each of which is 

 perforated by two primary aspinal pores. This tribe has arisen from the simpler 

 Phractaspida by reunion of the branches of the apophyses in each single spine. If 

 in Phractaspiis, their common ancestral form (PI. 137, figs. 1, 2), the neighbouring 

 fork-branches of both opposite apophyses in each radial spine become recurved and 

 united, they wdl produce a shield, which is perforated Ijy two pores and between 

 them by the spine itself. These two " primary aspinal pores " are characteristic of 

 all Ceriaspida ; among these Dorataspis itself is the most simple form. Its shell 

 exhibits therefore constantly forty asjjiual pores, and besides these a variable number 

 of " sutural pores " (in the sutures between the twenty plates). If in each suture 

 there be only a single pore, we get on the whole fifty-two or fifty-four pores ; if in 

 each suture there be two or three pores, that number becomes doubled or tripled. 



Subgenus 1. Doratasparium, Haeckel. 



Definition. — Shell with fifty-two sutures ; four polar plates on each pole of the 

 main axis meeting in one point (in the pole itself) ; therefore aU eight polar plates 

 pentagonal and of equal size. Spherical shell therefore composed of foui' (equatorial) 

 hexagonal plates and of sixteen pentagonal (eight tropical and eight polar plates). 



1. Dorataspis fusigera, n. sp. (PL 138, fig. 2). 



Shell with fifty-two sutixres and fifty-two sutural meshes, with four hexagonal and sixteen 

 pentagonal plates. Both aspinal meshes of each plate elliptical, twice to four times as broad as the 



' Z'oraiasjjts = Spear on the shield ; oo'ju, daTi;. 



