544 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
anus, which is generally closed in the specimens. The edges of the partition 
walls taper considerably upward, being quite thin above, rather thick below. 
Arms flattened at the back, stout, a little tapering at the upper end. They 
are composed of extremely short, tranverse pieces, which very slightly 
interlock; the four proximal joints single and resting between the protrud- 
ing upper parts of the interbrachials and interdistichals. In very mature 
specimens, in which these projections are comparatively longer, they some- 
times enclose 5 to 6 joints. Column tapering downward, the joints much 
the longest at the upper end; the nodal joints long, and wider than the 
intervening younger ones, their outer margins slightly convex; the joints 
near the root very short and of uniform size. The root is composed of hun- 
dreds of small branchlets, most of which are run out horizontally. 
Horizon and Locality. —Niagara group; Waldron and Hartsville, Ind., 
Green Co., O., and Chicago, Ils. 
Types in the American Museum of Natural History at New York. 
Remarks. — This species is extremely variable in form and proportions, 
but, as a rule, the cup in the older specimens is more elongate, and not 
unfrequently constricted near the middle, thereby producing a slight con- 
cavity at the sides. The base in some specimens is so broad as to give to 
the cup a subcylindrical outline. In all specimens, however, the base extends 
far out beyond the sides of the stem, and this, together with the unusual 
length of the first costals, and the extreme shortness of the arm joints, 
distinguishes it readily from all other American species of this genus. 
Eucalyptocrinus ovalis (Troost) Hatt. 
Plate LXXXIT. Figs. 1, 2, 3, 4, 5, 6. 
1849. Evxcalyptocrinus ovalis —Troost; Catalogue of Crinoidea. 
1874. Eucalyptocrinus ovatus (in error for E. ovalis) Harr}; first edit. 28th Rep. N.Y. State Mus. Nat. 
Hist., Plate 17, Figs. 12 and 18 (the error rectified in the second edit. of the same report in the 
explanation of the plates). 
1885. Eucalyptocrinus ovalis —W. and Sr.; Revision Paleoer., Part ITT., p. 134. 
A small species. General form ovoid, curving regularly from base to 
summit. Height to width as four to three in mature specimens, and six to 
five in very small ones. Greatest width a little above the top of the dorsal 
cup. Height of the cup, compared with the height of the partition walls, as 
two to three. Surface of plates smooth and without ornamentation ; the 
suture lines indistinct. 
