454 PALEONTOLOGY OF ILLINOIS. 



ever, attains a considerably larger size, and lias its second r;idi;il pjYcos 

 and those immediately succeeding- them turned outward more nearly 

 at right angles to the body. Its vault is also composed of more numer- 

 ous pieces, and not, as appears to be the case with this, provided with 

 a ventral tube. When its arms are preserved, they are also found to 

 be more numerous, owing to the more frequent bifurcation of the 

 divisions of its rays, so that it has eight arms to each ray, or forty to 

 the whole series, instead of only thirty. The general form of its body, 

 its depressed base, small size, etc., will readily distinguish it from all 

 the other inornate species known from the Burlington rocks. 



Locality and position Lower bed of Burlington group, at Burlington, 

 Iowa. Lower Carboniferous. The specimen represented by fig. G be- 

 longs to Mr. WACHSMUTH, and is numbered 196 in his collection. It is 

 the first example of this species showing the arms that has been figured, 

 the other published figures merely representing the body. 



PLATYCRINITES HALLI, Shumard ? 



PL 3, Fig. 3. 



Platycrinus olla, HAI.L. Descr. New Crinoidea, Prelim. Notice, p. 16, 1861 (not de Koninck and 



Le Hon, 1854.) 



Platycrinus Halli, SHUMAKD. Cat. Pal. FOBS., Pt. I, Echinod. Trans. Acad. Sci., St. Louis, Vol. 



IT, p. 388, 1866. 



BODY attaining a ratker large size, and composed of 

 tkick plates ; somewkat urn-shaped, or, wkeii tke arm-bases 

 are removed, approaching obovate, tke widest part being 

 above tke middle. Base more tkaii twice as wide as kigk 

 and regularly rounded below; sutures sometimes faintly 

 visible. First radial plates large, a little longer tkaii wide, 

 sligktly convex, and nearly oblong in general outline, tke 

 lower margin being a little rounded, and narrower tkaii 

 tke greatest breadtk above; sinus for tke reception of tke 

 second radials equaling about one-kalf tke greatest breadtk, 

 and excavated down nearly one-tkird tke lengtk. Second 

 radial pieces very small, or not near filling tke sinuses in 

 wkick they rest, and only showing a minute triangular sur- 

 face, wken tke succeeding pieces are attacked; succeeding 

 pieces small, short, and directed horizontally outward, 

 tke first two resting partly on eacli sloping side of each 



