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 

 nnil(> 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 i)i'oboscis. The ambulacral areas are convex and 

 the interanibulacral ar(>as abruptly depressed at the interradial 

 areas, so that the vault i)resents the same notched margin that 

 belongs to the calyx. There are sixteen ovarian apertures, 

 hut they are suuiU and situated close to the ambulacral open- 

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



This species when compared with B. inconsuettis, that has 

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

 different interradial and azygous areas and fewer plates in 

 th(-m: 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 ujion minor differ- 

 ences, lliat will occur to any one wlio reads the descriptions. 

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

 parison witli any of them is necessary. 



Found by S. A. Millei' in the Keokiik Group, at Booneville, 

 Missouri, and now in his collection. 



BATOCRINUS TCNOTHS, n. Sp. 



Plate I, Fifj. 31, basal victr; Fi(j. .'I'J. azyc/ous side vit w; Fig. 



33, summit vieic. 



Sjiecies medium size. Caly.K low, three times as wide as 

 high and ambulacral opiuiings directed horizontally. Radial 

 series roundcil. most strongly convex at the margin; iutci-radial 

 areas slightly concave, sui-face gi-auulai-; {•olumn i-ound. 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 njodm'ately concave, radiately 

 lined depression for the columnai' attachment. First primary 

 radials of unequal size and a litll(> wider than long, three 

 hexagonal, two heptagonal. Second primary radials quad- 

 rangular and about three times as wide as long. Third 



