464 THE CRINOIDEA CAMEEATA OF NORTH AMERICA. 



into a small lateral node. First regular interbrachials large, as wide as 

 long, and tuberculous ; followed by two smaller elongate, flat pieces which 

 rest between the arm bases. Anal plates three, longitudinally arranged ; 

 the first as large as, or larger than, the radials; the two others somewhat 

 smaller, supporting a subcircular mammillary protuberance, which is com- 

 posed of comparatively few large plates, and is pierced by the anus. The 

 posterior interradios has only two interbrachial plates, one to each side of 

 the second anal. Ventral disk sub-hemispherical, covered with five long, 

 slender spines. The posterior oral, which in other species is represented by 

 a central spine, is here nodose, and three times as large as the others. In 

 rays with four arm openings the spine-bearing plates are followed by two 

 double rows of rather large alternate pieces; but in raj's with two arms 

 they are followed by two single rows, the single as well as the double rows 

 enclosing a large subtrigonal interdistichal. Anus directed laterally, and 

 placed at midway between the posterior oral and the arm regions. Column 

 comparatively small, the facet for its reception deeply depressed, occupying 

 in different specimens from one sixth to one tenth the diameter of the basal 

 disk. 



Horizon and LocaUtt/. — Upper Burlington limestone ; Palmyra, Marian 

 Co., Mo., and Burlington, Iowa. 



Dorycrinus Eoemeri jMeek and "U'okthen. 

 Plate XLV. Figs. 15a, h. 



1868. Meek aud Woethen ; Proceed. Acad, Kat. Sci. Pbila., p. 8i6. 



1873. Meek and Wouthes ; Geol. Rep. Illiuois, Vol. V., p. 383, Plate 10, "Fig. 3. 



1881. W. and Sp. ; Revision Palseocr., Part 11., p. ISO. 



Of the type of D. missouriensis. Calyx a little longer than wide, lobed 

 at the arm bases, the dorsal cup obconical, nearly twice as high as the 

 ventral disk, gradually spreading to the top of the costals, thence abruptly 

 to the arms. Plates heavy, convex to nodose ; the suture lines not grooved. 



Basals somewhat expanding downward, truncated and moderatelj' con- 

 cave at the bottom, about twice as wide as high ; the interbasal sutures 

 slightly notched. Radials one third to one half wider than long, thickened 

 in the middle into moderately prominent, rather obtuse, transverse nodes. 

 Costals convex, quadrangular and pentangular ; the first rather large, wider 

 than long, the axillary a little wider in proportion. The latter supports 

 upon its sloping upper faces in the anterior and both posterior rays an axil- 



