304 New Species of Crinoidea from the 



stone, Burlington, Iowa. Collections of Rev, W. H. Bar- 

 ris and Dr. O. Thieme. 



Poteriocrinus lepidns (n. s.). Body broadly calyculate, 

 spreading to the base of the free arms, slightly lobed from 

 the incm-ving of the upper lateral angles of the first radial 

 plates. Basal plates very short, pointed above, extending 

 between the sub-radial plates; three fourths of their diam- 

 eter covered by the large pentalobate column. Sub-radial 

 plates of moderate size, wider than high, three hexagonal 

 and two sub-heptagonal, these being slightly larger than 

 the others. First radial plates larger than the sub-radials, 

 a little more than once and a half as wide as high, sub- 

 pentagonal, the upper lateral angles of four of them in- 

 flected, so as to give a somewhat heptagonal form ; the 

 fifth is quadrangular, with an apparent hexagonal form, 

 produced by the same cause. In at least four of the rays 

 there have been three radial plates, the two upper ones 

 free, and the last one bifurcating ; the second radial is 

 short, quadrangular. Anal plates four (in the specimen), 

 the first irregularly pentangular, resting upon two sub- 

 radial plates, and supporting on the right side the first 

 radial plate ; the second anal plate rests upon the truncat- 

 ed upper face of the sub-radial plate, and between the fust 

 anal and first radial plate on the left ; the third anal plate 

 rests upon the first and second, and the fourth anal plate 

 upon the summit of the second. Arms unknown. Sur- 

 face striato-granulose, the angles of the plates depressed, 

 giving a narrow indentation at these points. 



This species somewhat resembles P. calyciihis, but is 

 broader and much less constricted at the sides of the first 

 radial plates, and all the body plates are much wider in 

 proportion to the height. In that species also there are 

 but two radial plates, the second very long, equal in length 

 to the second and third radial plates of this species in an 

 individual twice as large. 



