30 Cincinnati Society of Natural History. 



of one YSiy to the tip of another, in a perfect specimen, to be about 

 two inches. 



It is distinguished from other species by the narrowness of the am- 

 bulacral furrow, by the absence -of any plates between the oral plates 

 and the plate at the junction of the marginal plates, and by the pecu- 

 liar form and position of the junctional plates. 



Pal^asterina speciosa, n. sp. (Plate I., fig. 7, dorsal view.) 



[Ety. — Speciosus, beautiful.] 



Pentagonal; rays obtuse at their apices; greatest distance from 

 point to point about 2|^ inches; breadth of bod}' between ra^^s abont 

 1^ inches, and distance from tip of ray to next adjoining tip on either 

 side about 1^ inches. 



The marginal plates are small and somewhat hemispherical, near the 

 termination of the rays, they graduall}^ enlarge and become square, and 

 then rectangular as they approach the disk, until at the narrowest part 

 of the disk or body of the fossil they are twice as long as wide. There 

 are about 50 marginal plates between the apex of one ray and the next 

 one adjoining, or in a perfect specimen of this size about 250. 



The back or dorsal side is covei'ed with numerous plates (probabi}' 

 in a complete specimen of this size there would be 1,000 or more), which 

 are very prominent in the center or somewhat conical, and seem to 

 have been joined together with deeply serrated edges. The plates 

 have from three to eight of these indentations, which give them a beauti- 

 ful star-like appearance. 



The ambulacral grooves are narrow and deep, as shown b}' the sharp 

 ridges on the back of the specimen. The small dorsal plates which 

 cover the ambulacral pieces are exfoliated in some places, and show two 

 rows of ambulacral plates coming evenl}^ together, and forming the 

 sharp ridge. 



This specimen was collected by W. C. Baruhart, on Twin Creek, 

 near Winchester, in Preble county, Ohio, in the upper part of the 

 Cincinnati Group. It was sold to J. W. Hai'vey, and by him sold to 

 C. B. Dyer, who placed it in his collection. 



Pal^asterina appkoxijiata, -n. sp. (Plate I., fig. 8.) 



[ISity .—Approximatus, near to; from its resemblance to P. sjieuiosa.] 



Pentagonal; ra3's more slender than in P. speciosa; greatest dis- 

 tance from point to point in the specimen figured 1.15 inches, and 

 bi-eadth of the body ^ inch ; another specimen from the collection of 

 Mrs. M. P. Haines, of Richmond, Indiana, measures from point to point 

 2.5 inches, and has a breadth of bodv of 9-lOth inch. 



