39 



have illustratfid it, because it has a pentagonal cohimn and 

 the cohunu was not preserved in tli(^ typo. It will be observed 

 that it is ma.tcnitied two diameters, without being as largo as 

 the type, which was iUiisti-atcd natural size. The arms ai)j)ear 

 t^ have been composed of longer i)lates tlum those belonging 

 ti the type an:l some other minor differences may be observed, 

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

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

 spesies was quite varialde. in si/.(_'. and possessed a small pen 

 t igoual column. 



.Found by R. A. Blaii- in th(^ Choute.iu limestone, at Si'dalia, 

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



CY.-\THOCKiNUS n[..\iKi, Miller and Gurley. 



This species was descril)ed and illusti-ated in Bulletin No. 7 

 of the 111. St. Mus. p. CiT. pi. IV. tigs. 11 to l."i, and in Bulletin 

 No. 8 p. 50, pi. Ill, tigs. I'l and I'l'. Some doubt was ex- 

 pressed as to the generic reference, and, i>robably, we sliould 

 have compared it, in the bulletin last mentiinied, with Mcspilo- 

 cririus of De Koninck and LeHon. But Mespilocrinus as detined 

 and illustrated has only three basal plates and C'ljalhocrinns 

 Idairi has five, which must separate them generically. Above 

 the basal plates Ci](dhocrinus blairi substantially agrees witli 

 Mespilocrinus, and, if it possessed only three basal i>lates, we 

 would refer it to Mespilocrinus. The general accuracy of De 

 Koninck-, in scientific matters, and the fact that we have nevei- 

 found him inaccurate in stating the structui-e of a crinoid, 

 leaves no doubt in our minds that Mispilncr uns has only three 

 basal plates. Two species of Mcspilocrinng have been described, 

 from the Burlington Grou^) of this country, by Prof. James 

 Hall. They arc distinct sptvies and are undoubted MespHo- 

 c i'lii.s. if he was not mistaken in the number of ba.sal plates, 

 which we have no right to assume. Possibly, the small spi'ci- 

 men figured, in Bulletin N;). 7, may bo distinct from the type 

 of Cyathocriiiis hlairi and if so a new genus may very well be 

 founded for their reception, l)ut the genus would belong to 

 the family Cyaihocrinidir and not t) the IcJilnjoeiiniiUr, where 

 we refer Lecanocrinns and .^fc^jnlocritius. 



