Manual of the Paleontology of the Cincinnati Group. 



only one row at apex ; ambulacral groove wide ; ambulacral plates 

 unknown. (Jour. Phil. Acad. Nat. Sci., vol. 3, p. 32, as Asterias.) 

 Locality. — Cincinnati, O. 



Remarks. — This species can hardly be said to have been described 

 by Locke, but the illustration given by him, although imperfect in 

 many details, is plainly a Palceaster. The brief description given 

 above has been drawn up from the figure. 



11. — P. speciosa (Miller and Dyer) sp. 1878. 



Pentagonal; rays obtuse at apex and about 2.50 inches from 

 point to point across body; breadth of body about 1.33 inches; mar- 

 ginal plates small and somewhat hemispherical, enlarging and becom- 

 ing square near the ends of rays; rectangular as they approach the 

 disc, until at the body they are twice as long as wide ; about fifty 

 marginal plates between the apex of one ray and the next one, thus 

 making about two hundred and fifty in all ; dorsal surface with many 

 plates, very prominent or somewhat conical in the center, each having 

 three to eight indentations, thus giving them a star-like appearance ; 

 ambulacral grooves narrow and deep ; two rows of ambulacral plates 

 coming evenly together and forming a sharp ridge. (Jour. Cin. Soc. 

 Nat. Hist., vol. 1, p. 30, as Palceaster ina. Paheasterina approximata 

 M. & D., Ibid. p. 31.) 



Locality. — Richmond, Ind., Waynesville and Preble Co., O. 



Remarks. — This species was originally described as a species of 

 Palasterina. The presence of the marginal plates would seem to 

 exclude it from that genus, and we have therefore placed it in Palce- 

 aster. The species described as P. approximata presents so few points 

 of difference that we regard it as a synonym. The dorsal surface of 

 approximata is described as " coarsely granular." The space between 

 the marginal and oral plates is stated to be filled by many smaller 

 plates, and the madreporiform tubercle is " conical and striated 

 longitudinally." The two latter features are not described under 

 speciosa. 



B . Ambulacral grooves narrow. 



12. — P. SH^EFFERI Hall, 1866. 



Pentagonal ; rays five, acute, seven-eighths inch long ; ambulacral 

 groove narrow, with two rows of ambulacral plates of about equal 



