200 MOUNTAIN LIMESTONE FOSSILS. 



epitheca is removed, the very fine, equal, costal striae are 

 brought into view, five in 2 lines at a diameter of 1 inch 2 

 lines j the outer, small, vesicular area is rather more than a 

 line wide, within which the sixty-five thick primary radiating 

 lamellae extend, about 4 lines towards the centre, leaving the 

 broad, flat, smooth, slightly undulated central portion of the 

 diaphragms about 6 lines in diameter in parts of the circum- 

 ference ; short secondary lamellae appear one between each of 

 the primary; lateral siphonal depressions strongly marked: 

 vertical section shows the outer vesicular area (at about the 

 above diameter) 1^ line wide, composed of about four very 

 oblique rows of small rounded cells, extending upwards and 

 outwards, from the broad deflected edges of the diaphragms, 

 which latter are thick, tolerably regular, nearly horizontal in 

 the middle, about three interdiaphragmatal spaces in 2 lines. 



This species is most nearly like Fischer de Waldheim's figure 

 of his Turbinolia [Caninia) ibicina, from which it difiers in the 

 greater number of the lamellae, &c. It difi*ers from the C. gigan- 

 tea in its smaller size, slender form, more regular and smoother 

 surface, much finer cells of the narrow outer area. I suspect 

 this may be the coral quoted occasionally by authors from moun- 

 tain limestone, under the name of the Devonian Cyathophyllum 

 flexuosum, to the figures of which it bears some resemblance in 

 external form, but from which it differs in its greater size, coarser 

 lamellar striae, deflected edges to the diaphragms, &c. 



Not uncommon in the carboniferous limestone of Kendal, 

 Westmoreland. 



(Col. University of Cambridge.) 



Diphyphyllum gracile (M'Coy) . 



Sp. Char. Corallum forming large masses of cylindrical tubes 

 2 lines in diameter, dichotomously branching and occasionally 

 coalescing laterally ; surface marked with sharp longitudinal 

 lamellar striae, about four in 1 line : vertical section shows 

 transverse, very slightly convex, thick, smooth, regular dia- 

 phragms reaching nearly across the tube, two interdiaphrag- 

 matal spaces in 1 line, bent downwards at the circumference ; 

 lateral vesicular area extremely narrow (less than one-fourth the 

 diameter), of about one layer of cells: horizontal section, primary 

 radiating lamellae thick, equal, extending less than halfway to 

 the centre, leaving the broad smooth diaphragms or clear 

 space in the middle nearly two-thirds the diameter ; between 

 each pair of primary in some specimens is an extremely mi- 

 nute marginal lamella. 

 The small diameter of the tubes distinguishes this species 



