50 



CYATHOCRINUS blairi, Miller & Gurley. 



Plale III, Fig. 21, azygous side view of an entire specimen; 

 Fig. 22, summit view of the same specimen. 



The authors described this species last year in Bulletin No. 

 7 of the Illinois State Museum of Natural History, p. 67, and 

 illustrated it on plate IV, figs. 11 to 15, but at that time, only 

 the calyx was known. Since that time Mr. R. A. Blair has 

 found a complete specimen which we are able to illustrate 

 If, from any cause, it was dwarfed, at the superior end, we 

 are unable to detect it; for it appears to be normal. 



The entire body with arms closed is spheroidal. The sec- 

 ond radials are as wide as the first, very short and quad 

 rangular. The third radials are nearly as wide as the second, 

 short, pentagonal, axillary, and support on each upper, slop- 

 ing side two secondary radials, which gives to the species ten 

 arms. The secondary radials are not of uniform size, but they 

 are so constructed and arranged as to cover the vault, seem 

 ingly. as close as vault plates would cover it, except a small 

 round spot at the center, which looks like the azygous orifice. 

 The depressions on the summit between the radial series, 

 gives it a slight pentalobate aspect when viewed from above. 

 The second azygous plate is semicircular with the arcuate side 

 up and is so closely surrounded above the first plate, by the 

 radials, that it looks like a plate forming pari of the vault. 



We have never before seen arms resembling those in this 

 species, unless those in the IchihyocrinidcB might he said i<> 

 have some similarity. The comparison, however, is remote. 

 Even the calyx suggested that it might nut prove to belong 

 to Cyathocrinus, and that doubt is increased by this complete 

 specimen. We do not, however, discover characters that we 

 call generic, to distinguish it. It is a very singular species. 



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

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



