1878.1 The Paleontologist. 



This species differs from A. Cincinnatiensis, Roemer, as defined and figured by Meek 

 and by Hall, in the form of the interradial plates, the curve and shape of the rays towards 

 and at the termination, and the convexity of the body. And from A. pileus. Hall, the 

 same variations may be stated, except the convexity, in which it resembles the latter. 



The fine type examples of this species are in the cabinet of Professor R. H. Holbrook, 

 of Lebanon, Warren County, Ohio, in honor of whom the name is given. 



Locality — near Lebanon, Warren County, Ohio. 



GENUS HELOPORA, (Hall.) 



HelOpora dendrina- (James.) Polyzoary dendroidal, starting from a slightly ex- 

 panding base, attached to other substances and spreading rapidly outward and upward; 

 anastomosing frequently; branches cylindrical, stirated longitudinally, and from 3^ to )^ 

 a line in diameter. Cells variable in form and arrangement, from circular to long oval, 

 in alternating rows in some parts, in others irregularly placed; cell apertures oblique, 

 with slightly raised margins, from 6 to 8 in the space of a line measuring longitudinally. 

 On and near the base the apertures are more elongated than above and arranged between 

 elevated flexuous lines. 



The best specimen examined of this species is about 2 inches in diameter across the top, 

 sub-circular in outline, lying in a depression in a fragment of limestone. Found by Mr. 

 Charles Schuchert, on Mt. Adams, Cincinnati. 



Helopora tenuis. (James.) Polyzoary minute, consisting of straight, angular or 

 cylindrical stems, with a single row of cells on the face exposed ; cell apertures oblong, 

 with raised margins, arranged between strong longitudinal lines, and separated about the 

 distance of their longer diameter ; about 6 cells in the space of a line, including the inter- 

 spaces. Examples examined are unbranched, from X ^^ 'A ^'^ 'n\c\\ long, and y^ or j\ of 

 a line in diameter. 



Some specimens have a depressed line on the highest part, and a row of much raised 

 oblique cell mouths on each side — others show only striated faces, no cells ; and some 

 have swollen terminations. All examples observed lie upon the surfaces of other sub- 

 stances, no detached specimens found, consequently but one face of any one example can 

 be seen. 



Locality — Cincinnati. 



Helopora Meeki. (James.) Polyzoary consisting of very small cylindrical or sub- 

 cylindrical stems ; sometimes branching dichotomously. About 6 cells in the space of a 

 line measuring their longer axes, and arranged in rows between strong elevated longitu- 

 dinal lines. The cells are generally opposite each other in the rows, but sometimes are 

 alternating; cell apertures long oval, margins not raised; length of fragments observed 

 from j4^ to ^ an inch ; diameter i of a line. 



All examples examined are attached to the surfaces of fragments of limestone. 



Locality — Warren County, Ohio. 



Helopora parvula. (James.) Polyzoary consisting of slender stems, branching 

 dichotomously at irregular intervals, more or less angular, about i/^ of a line in diameter. 

 Parts observed from ^ to ^ of an inch in length ; in most cases 2 or 3 rows of cells on 

 the exposed surface of the lower part, but above the last bifurcation, sometimes one row . 

 only. Cells generally in alternating rows, but in some examples they are nearly opposite 

 to each other, with quite strong, straight or zig-zag, more or less elevated lines between 

 the rows. The number of cells vary from 6 to 9 in the space of a line longitudinally, of 

 quite irregular shapes — circular, elliptical, angular and pointed — about their longer dia- 

 meter apart. Cell apertures, of unworn examples, have raised margins, arched above 

 and depressed below. Owing to the extreme frailness of the raised cell margins, they are 

 mostly more or less worn off. In many cases the apertures have an oblique, outward, 

 upward direction. The stems are often chain-like in appearance, seemingly angular, but it 

 is difficult to determine the exact form, no detached specimens being found, all lying on 

 the surface of or embedded in fragments of rock or shale. 



Associated with this species are cylindrical examples with one or two more rows of 

 cells, and btdbons upper terminations; the bulbs carry very small pores, which are not on 

 other parts of the fossil ; in other features they do not seem to differ from H. pai-vula. 

 .Should these prove, on further investigation, to be distinct, I propose the name Helopora 

 app7oximata . 



Locality — Obanon Creek, Clermont county, Ohio. 



