438 DR. G. J. HINDE ON NEW FOSSILS [Aug. 1 896, 



21. Descriptions of new Fossils from the Carboniferous Limestone. 



I. On Pemmatites constipatus, sp. nov., a Lithistid Sponge. 



II. On Pal^eacis humilis, sp. nov., a new Perforate Coral, 

 ivith Remarks on the Genus. III. On the Jaw-apparatus of 

 an Annelid, Eunicttes Reidle, sp. nov. By George Jennings 

 Hlnde, Ph.D., F.R.S., F.G.S. (Read April 29th, 1896.) 



[Plates XXII. & XXIII.] 



I. On Pemmatites constipatus, sp. nov., a Lithistid Sponge from 



THE YOREDALE BEDS OF YORKSHIRE. (PI. XXII. figS. 1, la-Ill.) 



Although the thick beds of chert in the Yoredale Series of North- 

 west Yorkshire are largely composed of the remains of siliceous 

 sponges, it is a matter of extreme rarity to meet with an entire 

 specimen of these organisms, and hitherto one has had to be con- 

 tent with describing the detached spicules of various forms with 

 which the beds are crowded. The discovery therefore by Mr. J. 

 Rhodes of a fairly complete sponge in this series of beds is, in itself, 

 of some interest, and still more when the sponge proves on exami- 

 nation to belong to the genus Pemmatites, Dunikowski, a genus 

 which, up to the present, has been known only from the Permo- 

 Carboniferous strata of Spitzbergen. 



The sponge in question, of which only a single specimen has, as 

 yet, been found, is discoidal, oval in outline, having both upper and 

 under surfaces nearly equally convex, and the margins comparatively 

 sharp. There are no indications of a point of attachment on the 

 underside, nor any traces of a cloacal funnel or depression on the 

 upper. It is 63 mm. in length, 48 mm. in width, and 22 mm. in 

 thickness. 



The canal system is very faintly shown ; but on the convex 

 upper surface there can be traced canal-apertures, about 0-5 mm. 

 in width, disposed in rows extending from near the centre to the 

 margins (PI. XXII. fig. 1). These appear to be the openings of 

 excurrent canals, which radiate from near the basal central portion 

 of the sponge in an oblique direction to the upper surface. ISTo 

 incurrent canal-apertures can be recognized on the surface of the 

 sponge, but in thin sections canals about 0*16 mm. in width, bounded 

 by spicules, are shown here and there, which may possibly belong- 

 to an incurrent system. (PI. XXII. fig. 1 1.) 



The skeleton-spicules have a straight or curved shaft, which may 

 be either smooth or notched, and with projecting tubercles, and the 

 extremities are inflated, or notched, or with small processes. They 

 are loosely interlocked together at the ends, and form open ana- 

 stomosing fibres (PI. XXII. figs, la-ll). The spicules range from 

 0-^ mm. to 0-4 mm. in length and about 0*03 mm. in thickness. 

 There are also irregularly distributed, in certain parts of the sponge, 



