Niagara Group. 419 



of which there are 35 in the space of 5 mm.; external striae very dis- 

 tinct ; there are frequent slender processes serving for attachment and 

 support; when decorticated the cysts are conspicuous ; height of coral- 

 lum 25 mm., diameter of the calix 25 mm., depth 15 mm.; cysts 

 prominent, varying from 1 to 2 mm. in diameter, covered by the rudi- 

 mentary lamellae which number 120, of uniform size, extending to 

 within 2 mm. of the center, and very finely granulated. This species has 

 a close general resemblance to some of the shorter forms of G. niaga- 

 rense, but the lamellae and denticulations are. very much finer. 

 Formation and locality. Niagara group, Louisville, Kentucky. 



CALCEOLA, Lamarck. 



Calceola pusilla, n. sp. 



Corallum simple, turbinate, more or less curved, anterior side flat ; 

 exterior with concentric wrinkles and fine but very distinct striae ; no 

 longitudinal striae visible; height 14 mm.; outline of calix nearly 

 semi elliptical, margin crenulated ; length from 10 to 12 mm., width 

 from 7 to 8 mm., sides quite regularly sloping to the center ; cysts 

 prominent, from 1 to 2 mm. in diameter. Commencing above the 

 center and continuing to the anterior margin is a very prominent 

 ridge, increasing in width as it approaches the margin. Compared 

 with C. Tennesseensis, the specimens (14) are smaller; the proportional 

 length is greater ; the curvature is usually less ; the lamellae of the 

 anterior portion of the calix are finer ; the cysts of the posterior por- 

 tion are much more prominent, and sometimes also covering the ante- 

 rior side ; the depression below the ridge of the anterior side, so con- 

 spicuous in that species, is obscure or entirely wanting in this one. 



Formation and locality, Niagara limestone, Falls of the Ohio. 



PETROSPONGIA. 



Cyathospongia, n. g. 



Body solid, turbinate, cyathiform; structure similar to astylos- 

 pongia. 



Cyathospongia excrescests. 

 Body turbinate, cyathiform, straight or slightly curved ; epithecal 

 covering smooth or obscurely striate and transversely wrinkled with 

 numerous radiciform processes or elongate nodes ; margins of the cup 

 oblique, thickened, marked with strong striae ; cavity deep ; internal 

 structure distinctly radiating from the apex or axis to the exterior, 



