19 



sion for the attachment of the column, and a small round 

 columnar canal. First radials a little wider than lon^:, three 

 hexagonal, two heptagonal. Second radials quite small, quad 

 rangular, and three or four times as wide as long. Third 

 primary radials about twice as large as the second, ])entagonal, 

 axillary and bear upon each upper sloping side two secondary 

 radials, the last one being axillary, and supporting in some 

 rays a single tertiary radial and in others two tertiary radials, 

 which arrangement gives to each ray four arms. There are, 

 therefore, twenty arms in this species and twenty ambulacral 

 openings to the vault. 



There are two plates in each regular interradial area, the 

 first one large and tumid, the second one much smaller. There 

 are five plates in the azygous area. The first one is in lino 

 with the first primary radials and rather larger than either of 

 them. It is followed by three plates in the second range, the 

 middle one being the smallest and quadrangular. Above the 

 middle plate there is a smaller and wider plate. The plates 

 in the azygous area look very much like the three primary 

 }'adials in a radial series, and the first regular interradial on 

 each side of the quadrangular middle plate, as shown in the 

 illustrations. No ovarian jtores can be detected. 



The vault is convex, without interradial depressions and 

 covered with polygonal convex plates. 11 Ijears u subc(Mitral 

 proboscis. 



This species is distinguished among those In-ariiig twenty 

 arms, by its general form and by the azygous jilati^s. 



It was found in the Bui'lington Group, in Adams county, 

 Illinois, and is now in th(> collection of ("hai'les L,. Faber. 



BATOCRINUS PETTISENSIS, n. sp. 



Plate II, Fig. 5, azygous side; Fig. fi, opposiie view. 



Species medium size, biturbinate, calyx and vault subequal. 

 Calyx rather broadly truncated, obconoidal, most ex])and('tl 

 opjjosite the azygous area, arm ojienings directed nearly hori 

 zontally, but not visil)h> in a basal \iew. No i-adial ridges. 

 Plates highly convex or tumid. 



Basal plates form an hexagonal disc that bears an hemis- 

 pherical depression for the attachment of tne colunin, and has 

 a diameter one lialf greater than the diameter of the column. 



