39 



have illustrated it, because it has a pentagonal column and 

 the column was not preserved in the type. It will be observed 

 that it is magnified two diameters, without being as large as 

 the type, which was illustrated natural size. The arms appear 

 t} have been composed of longer plates than those belonging 

 to the type and some other minor differences may be observed, 

 but there is such a striking resemblance between the two, that 

 we think they belong to the same species. If correct the 

 species was quite variable, in size, and possessed a small pen- 

 t igonal column. 



Found by R. A. Blair in the Chouteau limestone, at Sedalia, 

 Missouri, and now in the collection of S. A. Miller. 



cyathocrinus blairi, Miller and Gurley. 



This species was described and illustrated in Bulletin No. 7 

 of the 111. St. Mus. p. 67, pi. IV. tigs. 11 to 15, and in Bulletin 

 No. 8 p. 50, pi. Ill, figs. 21 and 22. Some doubt was ex- 

 pressed as to the generic reference, and, probably, we should 

 have compared it, in the bulletin last mentioned, with Mespilo- 

 cririus of De Koninck and LeHon. But Mespilocrinus as defined 

 and illustrated has only three basal plates and Cyalhocrinus 

 blairi has five, which must separate them generically. Above 

 the basal plates Cyathocrinus blairi substantially agrees with 

 Mespilocrinus, and, if it possessed only three basal plates, we 

 would refer it to Mespilocrinus. The general accuracy of De 

 Koninck, in scientific matters, and the fact that we have never 

 found him inaccurate in stating the structure of a crinoid, 

 leaves no doubt in our minds that Mcspilocr'nus has only three 

 basal plates. Two species of Mespilocrinus have been described, 

 from the Burlington Group of this country, by Prof. James 

 Hall. They are distinct species and are undoubted Mespilo- 

 c inns, if he was not mistaken in the number of basal plates, 

 which we have no right to assume. Possibly, the small speci- 

 men figured, in Bulletin No. 7, may be distinct from the type 

 of Cyathocriaits blairi and if so a new genus may very well be 

 founded for their reception, but the genus would belong to 

 the family Cyathocrinidce and not to the Jc/i'hyocrinuhv, where 

 we refer Lecanocrinus and Mespilocrinus. 



