If) 



Plates convex. Sutures depressed. Surfjiee very liiiely ^'r;iiiul!ir. 

 Coluinii round, medium size. 



Basals pentagonal and forni a cup aliout one-fourth the height of 

 the calyx, having a ccnicave depression around the column, which is 

 inserted in a hemispherii'al cavity. First radials large, convex, 

 longer than wide, four of them are of about the same size and rest on 

 straight faces of the basals: the other one is larger and rests in the 

 obtuse angle formed at the union of the two basals. The second 

 radials are very small, short, triangular, occupy about one-third the 

 width of the first radials. axillary and support on each upper sloping 

 side a single small secondary radial. The secondary radials are highly 

 convex, axillary and support on each upper sloping side the free 

 arms. There are. therefore, twenty arms in this species. The first 

 arm plates are small, round and convex. Whether the arms bifur- 

 cate after becoming free is unknown. The convexity of the first 

 radials leaves the small second radials resting on the inner margin, 

 which produces an api)arcnt constriction of the calyx at the top of 

 the first radials. ~ ■ 



The first azygous plate is in line with the first radials and is longer 

 than either of them. The superior end appears to curve over upon 

 the vault. 



The vault is not large, somewhat pyramidal by reason of the inter- 

 radial depressions, and covered with nodose and spinous plates. 



This species is so readily distinguished from T. trijagift and T. 

 coniiiients. its nearest allies, that no comparison is necessary. '-- 



Found by W. F. Pate, a collector and Principal of the Lebanon 

 schools of Kentucky, in whose honor we have proposed the specific 

 name, in the Kaskaskia (rroup. in Breckenridge county. Kentucky, 

 and now in the collection of Wm. F. E. (iurley. 



