RENIERA. 141 
transverse section, tapering evenly but somewhat abruptly, from the central disc 
to an obtuse termination. The rays forming the vertical axis, when complete, 
appear to be as long as the horizontal rays. There is considerable variation in 
the dimensions of the spicules ; the individual rays, measured from the centre of the 
disc, vary from 1:2 mm. to 3:2 mm. in length and from °3 to °6 mm. in thickness 
at their bases. 
The spicules of this species are characterised by the tapering conical form of 
the rays, and by the development of the rays of the vertical axis. In this latter 
feature they agree with spicules described by Prof. Schlitter from Devonian Rocks 
of the Hifel, under the name of Octaciwm rhenanum ;* but, judging from the figures 
and measurements given by Prof. Schliiter, the rays in our species, besides being 
larger, taper more abruptly. In Astrwospongia meniscoides,’ Dewalque, also from 
the Hifel, the spicules are larger than those of the present species, the rays are 
fusiform rather than conical, and no mention is made of the presence of vertical 
rays. In A. Hamiltonensis, Meek and Worthen,* from the Devonian of North 
America, the spicules are smaller, and do not appear to possess vertical rays. 
The forms described and figured were discovered by Mr. J. Smith, of Kalwin- 
ning, in decayed limestones. They are now of crystalline calcite, their surfaces are 
much eroded, and in some instances partially obscured by matrix. 
Distribution.—Middle Devonian: Newton Abbott, Devonshire. 
CARBONIFEROUS SPONGES. 
Sub-Order.—MonactinELLipa. 
Genus.—Reninra, O. Schmidt. 
1870. Die Spongien des adriatischen Meeres, p. 72. 
Syn.—Rayneria, Nardo; Pellina, O. Schmidt; Prianos, Gray. 
Sponges of variable form. The skeleton consists of acerate and cylindrical 
spicules, which are disposed so as to form a polygonal meshwork; the spicules 
held together at their ends by spongin. 
The connected skeletons of Sponges of this genus are unknown in the fossil 
1 «Sitzungsb. der niederrhein. Gesellsch. Bonn,’ p. 151; ‘ Zeitschrift d. deutschen geolog. Gesell- 
schaft,’ 1887, p. 23, Taf. ii, figs. 7—9. 
2 «Bull. del’Acad. Roy. de Belgique,’ vol. xxxiv, 1872, p. 24, pl. xxvi. 
3 ¢ Geol. Surv. Illinois,’ vol. iii, p. 419, pl. x, fig. 6. 
