MELOCRINID. 323 
Dolatocrinus speciosus (Hatt). 
Plate XXV. Figs. 4a, b. 
1862. Cacabocrinus speciosus — Hat; 15th Rep. N. Y. State Cab. Nat. Hist., p. 137. 
1881. Dolatocrinus speciosus — W. and Sv.; Revision Paleoer., p. 126. 
Of the type of D. major, but smaller; the dorsal cup proportionally 
higher, and provided with a somewhat deeper basal pit; the radials instead 
of being stretched out horizontally, gradually slope toward the basal con- 
cavity, without actually forming a part of it. It has but two distichals, and 
two arms to the ray instead of four; arranged in pairs with wide interspaces. 
Cross-section below the arm regions subpentangular. Plates apparently 
without ornamentation, their surfaces slightly convex; the median line of 
the plates following the rays gradually rising into a keel-like projection or 
carina, which passes up to the bases of the arms. This carina is higher upon 
the radials and costals, and thickened at the middle of each plate, where it 
is formed into a conspicuous elongate node; the node of the first costals 
more prominent than the others. 
Basals small, forming a shallow inverted basin, which is completely filled 
by the column. Radials larger than the costals, and about as wide as long. 
The first costal narrower and shorter than the second, and quadrangular ; 
the second obtusely angular above. Distichals 2 x 10, comparatively large ; 
followed by a lunate arm plate. Arm openings two to the ray, directed 
obliquely upwards, and those of the same ray packed closely together. First 
interbrachial almost as wide as long, with an obtuse lower angle, and its 
upper face broadly truncated ; the second about half the size of the first, its 
lateral faces parallel. The latter supports three plates, two upon its sloping 
lateral sides, and one upon the truncated upper face, which are followed by 
a row of interambulacral pieces. The interdistichal spaces contain two 
plates. Ventral disk slightly convex, each side containing four interambu- 
lacral plates, two of them larger and cuneate, touching the orals, the two 
smaller ones abutting against the secondary radial dome plates. The 
posterior oral is deeply wedged in between the four others, and considerably 
shorter. Anus almost central. 
Horizon and Locality. — Upper Helderberg group; Western New York. 
The specimen figured is from the collection of Wachsmuth and Springer. 
