35 



Anals one, quadrangular, length and width about equal, extending 

 above to a level with the summit of the adjacent radials, and rest- 

 ing below on the truncated upper margin of the right posterior sub- 

 radial. 



Arms and column unknown. 



This species is related to Eupach.formosus, Geol. Surv. 111., Vol. 5, 

 page 549, but differs from that in the proportions of its radial plates 

 and the subglobose character of its subradials. 



Position and locality: Chester limestone, Monroe county. 111. 



Illinois State collection. 



DICHOCKINUS HAMILTONENSIS. N. SP. 



Body small, length and breadth apparently about equal, though 

 from the crushed condition of the body plates, the exact proportions 

 of the body can not be accurately determined. Basals about half 

 as long as the radials, forming by themselves a low, shallow cup. 



Radials quadrangular, nearly once and a half as long as wide, 

 with a narrow, articulating scar at the summit for the reception of 

 the brachial series. 



Brachials three, the last one longer than those below, and support- 

 ing on its upper sloping sides the first arm plates. 



Arms two to each ray, as far as can be seen m the specimen be- 

 fore me, composed of short, wedge-shaped pieces, rounded exteri- 

 orly, and giving off from their longest sides rather strong pinnules. 



Column unknown. 



This species is nearly related to D.Jicus, of Lyon & Casseday, but 

 differs from that in the shorter form of the body, and m the num- 

 ber of its brachial pieces, which in their species is only two to each 

 ray. 



Position and locality: Upper part of the Keokuk limestone, 

 Hamilton, 111. 



No. 267 of Mr. L. A. Cox's collection. 



DICHOCKINUS COXANUS. N. SP. 



Body small, ovate in outline, pointed at the base and contracted 

 at the summit of the radial series, so that its greatest diameter is 

 near the base of the radial plates. 



Basal plates nearly three-fourths as long as the radials, forming 

 by themselves a rather deep cup. 



Radials longer than wide, lateral borders nearly straight, slightly 

 contracted at their summits, the articulating scar for the reception 

 of the brachial series occupying about one-third of the width of 

 their upper margins. 



Brachiar plates small, apparently two in number, the second one 

 being the longest, and supporting on its upper sloping sides the first 

 arm plates. 



Arms two to each ray, composed of short, rounded joints, which 

 give off strong pinnules from their inner borders. Anal side and 



