344 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 shghtly 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., 0., and Chicago, Ills. 



Tyjpes 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 (Teoost) Hall. 

 Plate LXXXIL Figs, i, 2, 3, 4, 5, 6, 



1849. Eucali/pfocrinus ovalis — Troost ; Catalogue of Crinoidea. 



1874. Eucalyptocrinus ovatus (in error for E. ovalis) — TLkll', first edit. 28th Rep. N. Y. State Mus. Nat. 



Hist., Plate VI, Figs. 12 and 13 (the error rectified in the second edit, of the same report in the 



explanation of the plates). 

 1885. Eucalyptocrinus ovalis — W. and Sp. ; Revision Palseocr., Part III., 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. 



