INVERTEBRATES. 99 



radials. Brachials as long as wide at bottom, constricted in 

 the middle, and supporting the first division of the rays. These 

 plates are all prominent in the center or sub-nodose, the axil- 

 lary plates more so than the plates below. 



Some of the rays after their first division on the second radial 

 divide once or twice more on the fifth and sixth plate, and pos- 

 sibly all may do so, though that cannot be determined from the 

 specimen at hand. 



Anal plates and column unknown. 



Position and locality: St. Louis limestone, St. Louis, Mo. 



Collector, A. H. Worthen. 



No. 2579 of the Illinois State Museum. 



GENUS BARYCRINUS, Wachsmuth. 

 BARYCRINUS SPURIUS. Hall. sp. 



PI. XIV, Fig. 4. 



Calyx broad basin-shaped, composed of massive depressed 

 convex plates. Uuder-basals spreading horizontally beyond the 

 columnar facet form a pentagonal disc. Basals hexagonal 

 counting three angles on their lower margins, except the one 

 on the anal side which is heptagonal. 



First radial plates wide, the autero-lateral ones longer than 

 the others; second radials very short; third radial somewhat 

 longer, and both nearly as wide as the first. The third radial 

 is angular above, and gives support to two stout arms, com- 

 posed of massive plates about as long as the second radials. 



First anal plate as large as the anterior basals, and hexa- 

 gonal counting thr/e angles on the lower margin. In the typi- 

 cal specimen figured in the Geology of Iowa, Vol. 1, part 2, 

 plate 18 figs. 7 and 8, there is a small quadrangular anal plate 

 intercalated between the large first anal and the right posterior 

 basal, but this seems to have been an abnormal character not 

 usually observed in this species. 



This specimen has been figured to show the character and 

 arrangement of the arms. 



Position and locality: Keokuk limestone, Warsaw, Illinois. 



Collection of A. H. Worthen. 



