Fossils in the Oxford University Museum.—II.On Two New Genera and Species of Crinoidea ( Brahmacrinus ponderosus and Cicerocrinus elegans )

Abstract

I. Brahmacrinus Ponderosus gen. et sp. nov. (P1. XVI, figs. 1 & 2.) This somewhat barbarically ornate crinoid is represented in the University Collection by two calyces, which are both devoid of arms and stem. One of the specimens is exceedingly well preserved, and affords a fairly complete knowledge of the structure of the calyx. In the British Museum (Natural History) five specimens of the same crinoid are displayed; these also are calyces without arms or stem. Some of the specimens in the British Museum were obtained from Preston (Lancashire), and some from Yorkshire; those in the Oxford University Museum are from the latter county, where they occur in the Carboniferous Limestone. The size of the calyx is fairly constant in all specimens, measuring, in that selected for description, 45 mm. in height by 40 mm. in maximum breadth. The dorsal cup is obconic in form, with the apex (corresponding to the base of the crinoid) truncate; the ventral disc is gently convex, and supports an excentric anal tube. The basals are large, and three in number; two are equal in size and larger than the third, which is the left anterior. The sutures, which are persistent, are not quite symmetric with regard to the radial plates, which they meet on one side of the median line. The basals, like the other plates of the calyx, are much swollen, except immediately over the sutures, which consequently lie at the bottom of a deep groove. The five radials are also large,