Vol. 55-] 



DEVONIAN EOCKS OF NEW SOTJTH "WALES. 



57 



Plagoniscus (?) YETFSTTJs, sp. nov. (Tcxt-fig. c, below.) 



The apical spine is elongate, with projecting lateral spines on either 

 margin : the basal spines are straight or slightly curved : they are 

 now imperfect. Beneath the central point is a short straight spine, 

 which may either be an extension of the apical spine or an inde- 

 pendent spine ; in this latter case the form can hardly be included 

 in Plagoniscus. Length of apical spine, 0'24 mm. ; thickness, 

 0"01o mm. ; the longest basal spine measures 0-105 mm. In 

 siliceous limestone. No. 245 3. 



[The figures are 



a = Plagoniscus cristatus, sp. nov. 

 b = PI. colligatus, sp. nov. 



all magnified 200 diameters.] 



I c = PI. {?) vetustns, sp. nov. 



I d=:Pl. (J) sp. 



Plagoniscus (?) sp. (Text-fig. d, above.) 



This form has, like the preceding, a short spine below the central 

 point of the basal spines and the apical ; both the apical and basal 

 spines are furnished with stout marginal prickles projecting at 

 right angles. Length of apical spine (imperfect), 0*2 mm. ; thickness, 

 0*015 mm. In the same rock with the preceding. 



