28 



the vault. The first azygous plate is in line with the first 

 primary radials and somewhat smaller; it is followed by three 

 plates in the second range and two in the third range, that 

 unite with the plates of the vault. 



The vault, though low, has more capacity than the calyx. 

 It is covered with polygonal, convex plates and bears a small 

 subcentral proboscis. The ambulacral areas are convex and 

 the interambulacral areas abruptly depressed at the interradial 

 areas, so that the vault presents the same notched margin that 

 belongs to the calyx. There are sixteen ovarian apertures, 

 but they are small and situated close to the ambulacral open- 

 ings and not as far back upon the vault as in B. inconsuetus. 



This species when compared with B. inconsuetus, that has 

 the same number of arms, will be found to have quite 

 different interradial and azygous areas and fewer plates in 

 them; there are fewer tertiary radials in the rays, and the 

 lobed rays and depressed marginal interradial areas serve at once 

 to distinguish it, without touching upon minor differ- 

 ences, that will occur to any one who reads the descriptions. 

 It is so different from all other described species that no com- 

 parison with any of them is necessary. 



Found by S. A. Miller in the Keokuk Group, at Booneville, 

 Missouri, and now in his collection. 



BATOCRINUS IGNOTUS, n. Sp. 



Plate 7, Fig. 31, basal view; Fig. 32, azygous side view; Fig. 



33, summit view. 



Species medium size. Calyx low, three times as wide as 

 high and ambulacral openings directed horizontally. Radial 

 series rounded, most strongly convex at the margin; interradial 

 areas slightly concave, surface granular; column round, medium 

 size. 



Basals form a subhexagonal disc that projects below the first 

 primary radials and has a diameter about twice as great as the 

 diameter of the column; it bears a moderately concave, radiately 

 lined depression for the columnar attachment. First primary 

 radials of unequal size and a little wider than long, three 

 hexagonal, two heptagonal. Second primary radials quad- 

 rangular and about three times as wide as long. Third 



