56 DR. G. J. HINDE ON THE EADIOLARIA IN THE [Feb. 1 899, 



Subclass NASSELLARIA, Ehreuberg. 



Order PLECTOIDEA, Haeckel. 



The rudimentary skeleton consists of simple or branched radial 

 spines, arising from a common central point or central rod. The 

 branched spines may be connected together by a loose, open mesh- 

 work. 



Genus PLAaiACANTHA, Claparede. 



The skeleton is formed by three radial spines arising from a 

 common central point, and corresponding to the edges of a three- 

 sided pyramid. 



Plagiacantha atjstralis, sp. nov. (PI. IX, fig. 23.) 



Only two of the spines and the basal portion of the third are 

 shown; they are nearly straight, simple, unequal in length, circular 

 in section, and gradually tapering. On their upper surfaces 

 there are close-set, minute pustules or blunted spines. Length 

 of spines, 0-215 to 0*18 mm.; thickness at centre, 0*02 mm. In 

 siliceous limestone. No. 245 3. 



Genus Plagonisctjs, Haeckel. 



The skeleton consists of four unequal radial spines arising from 

 a common central point : one vertical or apical spine being opposed 

 to three divergent or basal spines. 



Plagonisctts simplex, sp. nov. (PI. IX, fig. 24.) 



The three basal spines are simple, straight, conical, and in one 

 plane ; the vertical spine slender and curved. Length of basal spines, 

 0-06, 0-07, 0-08 mm. ; thickness, 0-01 mm. ; length of vertical, 

 0'085 mm. In siliceous limestone. No. 245 3. 



Plagonisctjs ceistatus, sp. nov. (Text-fig a, p. 57.) 



The basal spines, of which only two are shown, are simple, un- 

 even, with minute prickles ; the apical spine curved, compressed, 

 with stout prickles on one edge. Length of basal spines, 0*18 and 

 0*22 mm. ; thickness, 0*012 mm. ; length of apical spine, 0*18 mm. 

 In siliceous limestone. No. 245 3. 



Plagoniscfs colligatus, sp. nov. (Text-fig. b, p. 57.) 



The apical spine is fusiform, tapering to both ends and with 

 very minute prickles near its point ; the basal spines, of which 

 only two are shown, are straight near their origin, they are then 

 bent downwards and become furcate ; the rays are unequal. The 

 basal spines are connected with the apical by oblique siliceous 

 beams. Length of apical spine, 0-185 mm. ; thickness, 0-015 mm. ; 

 length of basal spine to end of furcate ray, 0*185 mm. Rare. In 

 siliceous limestone. No. 245 3. 



