Descriptions of new Fossils from the Carboniferous Limestone. I. On Pemmatites constipatus, sp. nov., a Lithistid Sponge. II. On Palæacis humilis, sp. nov., a new Perforate Coral, with Remarks on the Genus. III. On the Jaw-apparatus of an Annelid, Eunicites Reidiæ, sp. nov.

Abstract

I. On Pemmatities Constipatus, SP. Nov., A Lithistid Sponge from the Yordale Beds of Yorkshire. (Pl. XXII. figs. 1. 1 a-m .) 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 orgainisms, and hitherto one has had to be content 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,a nd still more when the sponge proves on examination 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 indiactions 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 (Pl. XXII. fig. 1). These appear