56 



There is ouly one regular interradial plate in each area, and it 

 is below the secondary radials and bears a central node. There 

 are pix plates in the azygous area. The first one is in line with 

 the first primary radials, and fully as large as either one of them. 

 It bears a central node and is followed by three plates in tiie 

 second range. A small plate is intercalated on the left of the 

 middle plate, and an elongated plate follows the middle plate of 

 the second ran:/e and unites with the plates of the vault. The 

 calyx is longitudinally depressed in the superior part of this area. 



The vault is convex, covered with convex, polygonal plates, and 

 bears a subceutral proboscis. It is depressed toward the azygous 

 area. 



This species will not be mistaken for any other twelve-armed 

 species. Its aflinity seems to be, through B. approximaius, with 

 B. vernenilianus. The proboscis may be smaller, the interradial 

 and azygous areas somewhat different and there may be other 

 minor differences, but the essential difference is in the arm form- 

 ula. B. approximcitus has thirteen ambulacral openings to the 

 vault, B. vernenilianus has fourteen ambulacral openings to the 

 vault, and this species has only twelve. 



Found in the Burlington Group, at Sagetown, Illinois, and now 

 in the collection of Wm. F. E. Gurley. 



BATOCRINUS APPBOXIMATUS, D. Sp. 



Plate IV, Fin. ^0, azygous side of an elongated jorm; Fig. 11, 



opposite view of the same: Fig. 12, lateral vieio 



of a broader form. 



Species below medium size, somewhat biturbinate. Calyx obco- 

 noidal, from one fourth to three fourths wider than high. No 

 radial ridges. First primary radials and interradials varj ing from 

 smooth to nodose. An ovarian pore by the side of each ambuia- 

 cral opening. Ambulacral openings directed horizontally. 



Basals form a round cup from two to three times as wide as 

 high and about one-half wider than the diameter of the column. 

 Plates beveled to the column, which is attached in an hemispheri- 

 cal depression. First primary radials nearly as long, or as long, 

 as wide, three hexagonal, two heptagonal, some are nodose and 

 others are smooth. Second and third primary radials together 

 much smaller than the first. Second primary radials quadrangu- 

 lar, about twice as wide as long. Third primary radials a little 

 larger than the second, pentagonal, axillary, and in the ray on 



