RENIERA. 143 



partly of crystalline silica. Traces of the axial canal are present in some 

 examples. 



These spicules are distinctly smaller and more evenly arcuate than those of 

 B. Carteri, from the Carboniferous of Ayrshire. They were obtained by Mr. J* 

 Wright from the decayed chert-bed at Ben Bulben, and described by Mr. H. J. 

 Carter, F.R.S., as " sausage-shaped spicules like those of some of the Reniera of 

 the present day. 



Distribution. — Upper beds of Carboniferous Limestone, Ben Bulben, Sligo, 

 Ireland. 



21. Reniera clavata, Hinde, sp. nov. Plate IX, figs. 5, 6 a, 6b. 



The spicules of this species are cylindrical, gently arcuate, with slightly inflated 

 extremities, their surfaces smooth and even. They vary from '36 mm. to *53 mm. 

 in length, and from "06 to "09 mm. in thickness. They are smaller than the pre- 

 ceding species, and characterised by their slightly tumid extremities. 



These spicules are the most abundant and widely distributed forms in the 

 Carboniferous Sponge-beds, which in places are filled with them. 



Distribution. — Yoredale series : Richmond, Arkendale, Harrogate, Yorkshire ; 

 Halkin, Henblas, near Holywell, Gt. Orme's Head, North Wales. Carboniferous 

 Limestone : Clitheroe, Lancashire. Middle Limestone or Calp series : near Dublin. 



22. Reniera virga, Einde, sp. nov. Plate IX, figs. 6, 6 a, 6 b. 



This name is proposed for elongated cylindrical spicules, smooth, evenly 

 rounded at both ends, and gently arcuate. In some specimens one end of the 

 spicule is slightly smaller than the other. They vary from '5 to '66 mm. in 

 length, and from *05 to "06 mm. in thickness. They are distinguished from 

 B. clavata by the absence of any inflation at their ends, and they are much more 

 slender forms than B. scitula. 



Distribution. — Carboniferous Limestone : Clitheroe, Lancashire. Yoredale 

 series : Richmond, Yorkshire ; Trelogan, Flintshire. Upper Limestones : Ben 

 Bulben, Sligo. 



