318 THE CRINOIDEA CAMEEATA OF NOETH AMEEICA. 



Larger than any of the preceding species. Calyx dej^ressed-globose, 

 somewhat flattened to near the top of the radials -, rapidly curving above^ so 

 that the walls of the dorsal cup near the arm bases are parallel to those of 

 the opposite side. Plates ornamented by interrupted ridges or lines of 

 small nodes, some of them radiating to the angles of the plates, others to the 

 sides ; those passing from the basal pit to the arm bases the strono-est and 

 almost continuous, rising to angular nodes in the centre of each plate. First 

 interbrachial provided with a strong central tubercle, and the ridges pro- 

 ceeding from the radials to the first distichals more prominent than the 

 others. Suture lines slightly channeled. 



Basal disk comparatively large, the upper angles projecting beyond the 

 column, the median portions concave, and the cavity surrounded by a cir- 

 cular rim. Eadials considerably wider than the costals, and also wider than 

 long. First costals twice as wide as long, the lower faces distinctly convex, 

 the upper a little concaA^e. Second costals longer than the first, slightly 

 increasing in width upwards, the sloping upper faces obtusely angular. 

 Distichals 2X2; the first equal to two thirds the size of the axillary costal ; 

 the two of the second row not more than half the size of the first, and those 

 of the second row separated by an interdistichal. Palmars two, short, lunate, 

 supporting the two primary arms. First interbrachial almost as large as any 

 two other plates of the calyx, and nearly as wide as long; followed by 

 a comparatively large hexagonal plate, which supports three others; the 

 two at the sides elongate and smaller than the middle one. Yentral disk 

 depressed-pyramidal. Anal tube subcentral, rising gradually from the disk. 

 Horizon and Locality. — Hamilton group; near Pavilion^ Genessee Co., 

 N. Y., and Columbus, 0. 



T/^pe in the American Museum of Natural History, New York. 

 Remarks. — We regard Cacahocrinus ghjptiis, var. intermedins, described 

 by Hall, and Dolatocrinus ornatus Meek, as mere variations of D. glyjptus, the 

 specimens only differing a little in the ornamentation. In the typical 

 D. glyptus, the ridges upon the plates are not continuous, but consist of 

 irregular series of elongate nodes ; while in the specimens of D, glyptus, var. 

 intermedins they are generally not interrupted. D. ornatus was described by 

 Meek as coming from the Hamilton group of New York. 



