464 THE CRINOIDEA CAMERATA 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 interradius 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 rays 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 Locality. — Upper Burlington limestone; Palmyra, Marian 
Co., Mo., and Burlington, Iowa. 
Dorycrinus Roemeri Meex and Worruen. 
Plate XLV. Figs. 15a, b. 
1868. Mexx and Worrnen; Proceed. Acad. Nat. Sci. Phila., p. 346. 
1873. Mupsx and Wortuzn; Geol. Rep. Illinois, Vol. V., p- 3838, Plate 10, Fig. 3. 
1881. W. and Sp.; Revision Paleoer., Part IT., p. 180. 
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 erooved. 
Basals somewhat expanding downward, truncated and moderately 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- 
or maaan a 
~g— 
