274 Neiv Species of Crinoidea from the 



a brachial plate, chiving four orms to each of these rays, 

 and two to each of the first, making the brachial formula 

 ^\ = 14. 



First interradial plate eight sided, less than half the 

 size of the first radial plates, supporting two narrow, elon- 

 gate plates, one six-sided and one four-sided. First anal 

 plate equal to the first radials, heptagonal, sui)porting three 

 smaller plates in the second range ; the middle one heptag- 

 onal, twice as large as the lateral ones, and supporting on 

 its upper edges two small plates which extend to the small 

 aperture. The anal area is low, composed of few com- 

 paratively large plates. Dome composed of medium 

 sixed, sub-nodose plates, surrounding the bases of the 

 spines, with one large and more elevated plate above the 

 anal area. Surface of body plates smooth ; first radial and 

 first anal plates depressed-convex. 



This species is of the type of A. Missouriensis, (Report 

 of Missouri Geol. Survey, pi. 8, fig. 1 ;) but difters in the 

 form of the body, which is more cylindrical and less spread- 

 ing above, — in the arrangement of the arms, the less pro- 

 truding anal area, and the body plates being without nodes. 



Geolo(]^ical formation and locality. Burlington lime- 

 stone, Burlington, Iowa. Collection of C. A. White. 



Actinocrinus clivosus (n. s.). Body urn-shaped, spread- 

 ing above the first supra-radials to the arm bases ; dome 

 moderately convex, composed of rather large plates, and 

 surmounted by a sub-central proboscis. Basal })lates 

 large, massive, irregularly thickened, and projecting over 

 the column, the base of each plate being deeply concave, 

 the angles extending below, and separated at the sutures 

 by a deep indentation, which gives six pendent angles to 

 the base. First radial plates of height and width nearly 

 equal ; second radial plates comparatively small, quadran- 

 gular or sub-pentagonal ; tiiird radials smaller than the 

 second, hexagonal or heptagonal, very obtusely angular 



