144 BRITISH PALEOZOIC SPONGES. 



23. Reniera gracilis, Hinde. Plate IX, figs. 7, 7 a, b. 



1885. Reniera gracilis, Hinde. Beds of Sponge-Remains in Lower and Upper 



G-reensand, Phil. Trans., p. 436, pi. xli, 

 figs. 1, 1 b. 



Cylindrical spicules, gently arcuate, smooth, with evenly rounded ends. Average 

 length *4 mm., thickness "05 mm. These spicules correspond closely with those 

 described under the above name from the Lower and Upper Glreensand of Surrey 

 and Devonshire. They are distinctly shorter than the spicules of R. virgata. 

 Distribution. — Yoredale series : Richmond, Yorkshire. 



24. Reniera Zitteli, Pocta. Plate IX, figs. 8, 8 a — 8 c. 



1884. Renteba Zitteli, Pocta. Sitzungsber. der konigl. bohm. Gesellsch. der 



"Wiss., vol. 1884 (1885), p. 8, pi. i,figs. 10—14. 



1885. — — Hinde. Phil. Trans., p. 437, pi. xli, figs. 4—4 e. 



Acerate spicules, straight or gently arcuate, smooth, either fusiform and gently 

 tapering to both ends, or nearly even throughout and somewhat abruptly pointed. 

 Length from "3 to *5 mm. and from *03 to '04 mm. in thickness. 



These Carboniferous spicules cannot be distinguished from the forms occurring 

 in the Greensands of Surrey and Devonshire, and in the Cretaceous strata of 

 Bohemia and Westphalia. 



Distribution. — Yoredale series : Richmond, Yorkshire ; Halkin, Henblas, near 

 Holywell, North Wales. Carboniferous Limestone : Clitheroe. Upper Limestone 

 series : Benachlan, Ben Bulben, Sligo. 



25. Reniera bacillum, Hinde, sp. nov. Plate IX, fig. 9. 



Very slender cylindrical spicules, either gently curved throughout their length, 

 or somewhat abruptly incurved near one or both ends. Their surfaces are smooth, 

 and their extremities evenly rounded. They vary from '23 mm. to '5 mm. in length, 

 and -02 mm. in thickness. These forms are readily distinguishable from those 

 previously described by their slender proportions. They are extremely abundant 

 in some of the cherty Sponge-beds, which are mainly composed of their minute 



