36 



column unknown. The surfaces of the body plates are marked by 

 ob.-cure longitudinal ridges that will serve to distmguish the species 

 from any one hitherto described from this horizon. 



Position and locality : Upper part of the Keokuk limestone, Ham- 

 ilton, 111. 



No. 14 of Mr. L. A. Cox's collection. 



TALAROCEINUS OVATUS. N. SP. 



Body above the medium size, ovate in general outline, lobate as 

 viewed from above or below. 



Basals about half as high as wide, impressed below, and pentag- 

 onal above, with a slight depression at their lateral Ijorders. 



First 1 adials about one-third longer than wide, the anterior one 

 pentangular, the others quadrangular, and all protuberant. The suc- 

 ceeding radials not visible. 



The first anal is as large or a little larger than the first radials, 

 heptagonal, having four distnict angles above and three below. It 

 is succeeded by three small anals, the central one of which is pen- 

 tagonal, and rests on the truncated summit of the first anal, while 

 the other two, the form of which can not be clearly seen, rest upon 

 its upper lateral angles. Above this there is one or two series of 

 very small plates surrounding the anal opening. 



The vault is composed of very small, smooth plates, except the 

 cential one, which is larger, and produced mto a pointed spine. In 

 (me of our specimens there is a spine- bearing plate, between the 

 arm openings and the central spine on two of the rays. Arm open- 

 ings two to each ray. Arms and column unknown. 



This species is related to T. sexhhatm, (Shumard's sp.) but differs 

 from that in its more symmetrical form, its less protuberant radial 

 and anal plates, and less nodose summit. 



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



Illinois State collection. 



AGASSIZOCRINUS PAPILLATUS. N. SP. 



Body rather below the medium size, subovate, width at the sum- 

 mit 01 the radials a little more than the length, composed of mas- 

 sive, slightly rounded plates that are separated by well-defined and 

 deep sutures. 



Basals pentagonal, about as wide as long, and rounded below, 

 where their inner margins form the walls of a very small pentapetal- 

 ous opening for the attachment of a very delicate round column, 

 two or three joints of which remain attached to one of our speci- 

 mens. 



Subradials three hexagonal, counting three angles V)elow, and two 

 on the posterior side heptagonal, length and breadth about e(pial. 



lladials pentangular, nearly twice as wide as long except the two 

 posterior ones which are rather narrower than the others. 



