768 THE CRINOIDEA CAMEEATA OF NORTH AMERICA. 



supporting two arms from each division, or four to the ray. Arms divergent, 

 long and rather slender ; composed of moderately long cuneate pieces, which 

 gradually interlock, and from about the eighth plate are strictly biserial. 

 Anal plate narrower than the radials, its sides almost parallel. Form and 

 position of the anus unknown. Column round and small. 



Horizon and Locality. — Upper and Lower Burlington limestone ; Burling- 

 ton, Iowa. 



The specimens figured are in the collection of Wachsmuth and Springer. 



Remarks. — Hall's D. pocillum, Bull. I. N. Y. State Museum, Plate 2A, 

 Figs. 16 and 17, is a large example of this species, and his figure 14 on 

 the same plate is pirobably D. Icevis. 



Dictiocrinus angustus White. 



Plate LXXVI. Fig. 11. 



1852. White ; Proceed. Bost. Soc. Nat. Hist., p. 19. 

 18S1. 'W. and Sp. ; Eevisiou Palseocr., Part II., p. 8.3. 



A small and slender species. Calyx nearly twice as high as wide ; sub- 

 ovoid ; very little spreading above the basals, the upper end slightly con- 

 tracting. Plates without ornamentation or convexity beyond their general 

 curvature. Suture lines not grooved or indented. 



Basals forming a cup with rounded sides ; the face for the attachment of 

 the column not protuberant ; it is circular and proportionally larger than in 

 the preceding species. Radials almost twice as long as their width at the 

 basi-radial suture ; facets wide, but shallow, and pointing upward. Costals 

 two, forming a syzygy, each plate marked by two small nodes. Distichals 

 three ; the two lower, which form a second syzygj', together but little larger 

 than the third, or axillary. Arms four to the ray, composed of a single row 

 of slightly wedge-shaped plates. Pinnules long. Anal plate a little wider 

 belo-w than at the top. All other parts unknown. 



Horizon and Locality. — Upper Burlington limestone j near Burlington, 

 Iowa. 



Types in the Museum of Comparative Zoology. 



Remarks. — This species is so closely allied to D. Icevis Hall from the 

 Lower Burlington limestone, that there is reason to doubt whether it is 

 a good species; however, as a rule, the specimens from the upper bed are 

 smaller, the arm plates less cuneate, and there are, so far as observed, always 

 four arms to the ray, which are invariably given off from the third distichal. 



