[ 



Upper Helderherg Group. 151 



between apertures smooth and slightly concave, intercellular space of 

 the interior vesiculose. 



Locality — Falls of the Ohio river. 



LiCHEXALIA COXULATA, 11. Sp. 



Eamose, hollow, or lamellate expansions; thickness varying from 

 .50 to 5 mm., sometimes branches solid; cells tubular; apertures cir- 

 cular, diameter .20 mm., margins unequally elevated, inclining toward 

 the center of and constricting the aperture, giving the appearance of 

 tumid lips; margins of adjacent cells in contact; surface with numer- 

 ous rounded elevations, the centers of which are distant .50 mm.; 

 height 1.50 mm. ; cells of maculaB larger than others and radiating; 

 cell-tubes septate; septa 5 in space of one mm.; intercellular space of 

 interior vesiculose. This species is easily distinguished by its promi- 

 nent conical elevations. 



Locality — Falls of the Ohio river. 



LiCHEXALIA CLIVULATA, 11. sp. 



Lamellate or cylindrical expansions ; diameter of cell-apertures .17 

 mm.; margins unequally elevated, the stronger portion ^Drojecting over 

 the aperture, and having two minute denticulations; around each aper- 

 ture a narrow obscurely polygonal depression; surface with numerous 

 elevated macular, centers distant from two to three mm., bases olten 

 in contact with each other; surface being composed of rounded eleva- 

 tions, and finely granulose. 



Locality — Falls of the Ohio river. 



LiCHEXALIA CARIXATA, U. Sp. 



Intercellular space vesiculose; vesicles large, irregularly disposed, 

 apertures circular, oblique to the surface, diameter .28 mm., irregularly 

 arranged, margins unequally elevated, one side projecting over and 

 constricting the aperture ; the upper portion of the cell-wall is some- 

 times exposed for nearly two-thirds the entire length ; along the 

 middle of the wall is a sharp slightly elevated carina, sometimes pro- 

 jecting beyond the margin as a denticulation ; on the surface are 

 maculae, the centers of which are depressed and without apertures ; 

 cells in contiguity to the maculae larger than the others, and the 

 radiating space between apertures with minute pits. 



Locality — Falls of the Ohio river. 



LiCHEXALIA PERMAKGIXATA, n. Sp. 



The specimens observed are celluliforus on both sides; cell-aper- 

 tures .40 mm. in diameter, irregularly arranged, margins strong; on 



