100 I 'A L/EONTOLOGY OF ILLINOIS. 



BARYORINUS TUMIDUS. Hall. sp. 



PI XIV, Fig. G. 



Cyathocrinus tnmidus Hall. Geology of Iowa, Vol. 1, part 2, pago (i2l. I'l. XVIII, Figs. 



1, a. b. 



"Calyx basin form, shallow, the plates thick and tumid. 

 11; i sal plates small; their area nearly occupied by the column, 

 and presenting a small pentapetalous opening in the cenler. 

 Subradial plates with the bases nearly straight, pentagonal, 

 except the one on the anal side which is hexagonal; each plate 

 prominently convex or tumid. Radial plates somewhat un- 

 equal, very thick and broad, convex in the middle; articulating 

 faces nearly in a plane with the axis. First anal plate quad- 

 rangular, small. 



Surface finely granulose or grauulose-striate towards the mar- 

 gins of the plates. 



The base is more prominent than the surrounding subradi;il 

 plates; in which character it differs from ('. buUntiin, the sub- 

 radials being less prominent, and the radials larger and more 

 equal in size." 



The above is the original description of this species, the type 

 specimen consisting of the calyx only. In the figured specimen 

 on PI. XIV, the arm formula is clearly shown. On three of the 

 rays, to-wit, the anterior and the posterior laterals, there are 

 two brachials, the first one very short and nearly as wide as 

 the radials, the second a little longer, obtusely angular above, 

 and giving support to the two divisions of these rays. On the 

 other rays there are no brachials, each sustaining a single arm 

 supported on the upper surface of the radial plates, giving eight 

 arms to each individual. Arms composed of massive plates, 

 decreasing very gradually in breadth from their base upwards. 



Position and locality: Keokuk limestone near Hamilton, 

 Hancock county, Illinois. 



Collection of A. H. Worthen. 



GENUS DORYCRINOS. Itemer. 

 DORYCRINTTS MississiPPiENSis. Roemer. 



PL XII, Fig. 4, 



Body broadly urn-shaped, dome convex, with six long slender 

 spines, five of which are situated immedialy above the summit 



