29 



III till' subpsntagonal outliiio of tlu' calyx, short, form, and in 1lic 

 cliaraoter of the vault this species allies itself with A(i<in'cui-n'- 

 iiHs; but in the plates of the calyx, and in their arrangement, it is a 

 true Balocrinus. If the arms were preserved, we might be disposeii 

 to refer it to Af/((ricncriniix, notwithstanding the plates and form of 

 the calyx. We have n^ferred it to Baiocrinus with doubt. If there 

 has ever been a link discovered that connects Bdlocriiiiis with 

 Agfiricocrinxs. hy any chain of development, it is to be found, in 

 this species. All authors who lay stress upon the characters of the 

 vault will unhesitatingly I'efer this species to Af/ariaicrlinis. But 

 no eighteen armed Af/(irirocriiiits has ever been found, in thi' Burl- 

 ington Group, and only one in the Keokuk, and it is a pronounced 

 Agarirncrinux. Typical Agarivocriinis appear in the Chouteau 

 with ten and twelve arms and they are quite as early as any Buhicri- 

 iitis. Bdfocriniis with eighteen and more arms are common in the 

 Burlington. This cannot be the species through which B((l<icriinis 

 developed into AgnricocriiiKs, nor through which .Igni-icdcriiiiis dr- 

 veloped into Biifocriinis, because it is not found in rocks early 

 enough for such transition. It is only indicative of an apparent 

 affinity, when both genera were in the mature state of their exist- 

 ence. The stratigraphical position with the eighteen armed struct- 

 ure is in favor of classifying it with Baiocrinus. 



Found in tlie Burlington Ciroup, by R. A. Blair, near Sharon, in 

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



BATOClilXl'S |)OTGl..ASSI. n. Sp. 



/'idle TI, Fig. 'J<i, view oppoiiite ilie (izi/gnuf! (irea. 



Species medium size, biturbinate. Calyx obconoidal, about twice 

 as wide as high. Radial ridges rounded, and all the plates radiateiy 

 sculptured. Truncatetl only the diameter of the column. 



Basals form a very short hexagonal disc. First primary i;idials 

 much wider than long, three hexagonal, two heptagonal. Second 

 Ijrimary radials about half as large as the first, and about half as 

 long as wide, quadrangular. Third primary radials larger than the 

 second, pentfigonal. axillary, and support on each uitiirr slojiing side 

 a single secondary radial which is axillary, and, upon the distal sides. 

 supx^ort four tertiary radials, before the arms become free; upon each 

 proximal side there is a single tertiary radial, which is axillary and 

 supports three quaternary radials before the arm becomes free. 



