90 PAL.KX OTOLOGY OF ILLI N< >IS. 



Column rather stout where it joins the body, composed of 

 slightly projecting plates that diminish gradually in size below. 

 Position and locality : Devonian shales, Buffalo, Iowa. 

 Collection of A. H. Worthen. 



POTERIOCRINTJS ROWLEYI. (sp. 11OV.) 

 PI. XIV, Fig. !>. 



Calyx short, cup shaped, twice as wide as high, with a well 

 defined suture betw r een the radial and brachial series. 



Brachials on the anterior ray two, a little longer than wide. 

 the first quadrangular, and the second pentagonal, giving sup- 

 port on its upper angles to the first arm plates. These arms 

 continue single after their first bifurcation. 



The right antero-lateral and the left postero-lateral rays, 

 have but one brachial each, which is pentagonal, length and 

 breadth nearly equal, and gives support to the first division 

 of the rays. These divisions bifurcate again on the fourth 

 plate, giving four arms to each of these rays. 



Arms stout for a species of this size, composed of joints about 

 as wide as high, gradually tapering to their extremities. Anal 

 side not visible. 



Column round, and composed of alternately thick and thinner 

 pieces, the former slightly projecting. 



Position and locality: Chester limestone, Monroe county, 

 Illinois. 



Collector, A. H. Worthen, 



No. 2575 of the Illinois State Museum. 



Named in honor of Mr. R. R. Rowley, of Louisiana, Mo. 



POTERIOCRINUS SPINULIFERUS. (sp. 11OV.) 

 PI. XVII, Figs. 1-la. 



Body short, saucer shaped, about three times as wide as high, 

 and composed of rather massive plates separated by well-defined 

 sutures. 



Base depressed, and uuder-basals concealed in the basal de- 

 pression. Basals proportionally stout, pentagonal, the lower 

 angles curving into the basal depression. Radials short and 

 pentagonal, truncated squarely on their upper margins for the 



