12 The Paleontologist. [Sept. 14, 



The specimens from which this description is made, are from ^ to '^ a line in thick- 

 ness, grown all round different species of crinoidal columns. 



Found in the middle and upper beds of the Cincinnati Group near Milford, Clermont 

 Co., O., and other localities. 



PxEVUS CERAMOPORA, (Hall.) 



Ceramopora Whitei. (sp. nov.1 (James.) Polyzoary a thin crust grown upon 

 foreign substances, — generally corals — sometimes spread all round, and in and over the 

 inequalities of very irregular surfaces of bodies of considerable size — 3x6 inches, less or 

 more. The cells seem to be mostly direct*, but in some places may be slightly oblique and 

 very little elevated at the apertures. An average of about 10 cells in the space of a line 

 measuring in any direction, very irregular in shape and size — circular, oval, triangular 

 and other forms. Distributed irregularly over the surface are slightly elevated areolae, 

 where the cells are generally smaller than the average on other parts. Cell walls very 

 thin. h. few minute tubules between some of the larger cells. 



This species differs from Professor Nicholson's typical form of C. Ohioensis in most of its 

 features materially. The cell apertures are disposed in a confused manner (seemingly) 

 over the surface of various shapes and sizes, and but slightly oblique or elevated, if at all, 

 and somewhat smaller. That species is generally found grown upon shells, this rarely. 



C. C/i?(7<'«jw is described as having the " cells arranged in intersecting diagonal lines, 

 and disposed in a somewhat concentric manner round more or fewer central points ; their 

 upper walls thin and arched ; the cell-mouths oblique, and when most perfect, semi-circu- 

 lar in shape. About 8 cells in the space of one line." Our species is quite different from 

 this description, the cells ttoi being arranged in "intersecting diagonal lines" in "a 

 somewhat concentric manner round fewer or more central points." 



Named in honor of C. A. White, M.D., Paleontologist of the U. S. Geological Survey. 



Position and locality — Lower Silurian, Cincinnati Group, at Cincinnati. 



Ceramopora radiata. (sp. nov.) (James.) Polyzoaryconsistingof agroupof cell 

 tubes radiating from a central point in all directions ; the lines of tubes not always taking 

 a direct course but turning a little either way at some points, with interstatial rows coming 

 in. Tubes slender, tapering gradually and seemingly attached to each other at theirbases 

 at the central point ; but outside of that point each succeeding tube springs from the 

 under side of the one belovir, the lower one partly overlapping the one above, and rising at 

 various angles as they gradually expand. Cell apertures circular or oval, the lower lip 

 extending beyond the upper, and arranged in alternating diagonal rows; diameter of cell 

 apertures about ^^ or yV of a line. Between some of the rows of tubes, near the center, 

 are exceedingly small pores, shown more distinctly on some parts than on others, in a 

 specimen slightly weathered. 



The example from which this description is made is sub-circular in outline, about 4 lines 

 in diameter, and lies in a depression of a fragment of coral, to which it is attached. 



This species resembles C. labeculia. Hall, from the Niagara Group, Ind., as figured, 

 but not described in the 28th Regents Rep. on the N. Y. State Cabinet. The cells are 

 more distinctly individualized than that figure instead of less so, as stated by Prof. H., in 

 reference to labeculia. 



Position and locality — Lower Silurian, Cincinnati Group, at Cincinnati and vicinity. 



GENUS PLEUROTOMARIA, (De France) 



Pleurotomaria OhioeilsiB. (James.) (Proposed for Z'. trilineata, which was pre- 

 occupied.) The most distinguishing feature of this species is the three delicate, sharp 

 longitudinal lines on the middle of the whorls, from :he aperture to the apex, which 

 .occupy a space of about ^ a line; a fourth line, less distinct, may be seen on most speci- 

 mens, when perfect, about half way between the outer ones of the three and the suture. 

 The fine transverse striae curving forward below and backward above the three lines 

 cross the other line in one direction without interruption. 



Pleu- Otomaria dryope. (Billings.) I have specimens resembling this species — 

 except being smaller They are mostly casts, but the ones with the outer shell in good 

 condition show the characteristic curved striae. Should they prove distinct on further 

 examination, I propose the specific name carinata, in allusion to the sharp, prominent 

 keel along the center of the whorls. The casts are fully as sharply carinate as the speci- 

 mens retaining the outer shell. 



Position and locality — Upper beds of the Cincinnati Group, Clinton Co., O. iMr. Bil- 

 lings' species were from the Trenton Group, Canada. 



