276 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
the plates somewhat smaller. Nothing is known of the ventral disk, the 
anal opening, and the upper portions of the arms. Column strong, round ; 
composed of alternate thick and thin joints, all rounded along the edges, the 
former twice as high as the latter, and somewhat wider, Axial canal large, 
pentalobate. 
Horizon and Locality. — Trenton limestone ; City of Ottawa, Canada. 
Remarks. — This species has a superficial resemblance to certain species 
of Archeocrinus, and in 1881 we referred it to that genus. But on examin- 
ing the type specimen from the Canada Survey Museum we find it has no 
infrabasals, and the angles of the axial canal are interradially disposed. 
(2?) Glyptocrinus Fornshelli S. A. Mitter. 
Plate XX. Fig. 3, and Plate XXI. Fig. 5. 
1874. S. A. Minter; Cincin. Quart. Journ. Sci., p. 348. 
1881. W. and Sp.; Revision Paleoer., Part IT., p. 188. 
1883. S. A. Mitter; Journ. Cincin. Soc. Nat. Hist., Vol. VI., p. 227; and North Amer. Geol. and Pale- 
ont., p. 248. 
Calyx elongate, obconical; dorsal cup almost twice as high as wide, its 
sides convex. Plates delicate and beautifully ornamented, being traversed 
by sets of from five to seven small ridges, a set directed to each side of 
the plate, and each set continued upon adjoining plates. The ridges of the 
same set are parallel, those of different sets meeting at an angle at the 
middle of the plates, and being so arranged as to form numerous rhombs, 
each containing two sets of included triangles. Upon the radials and costals 
the median ridge is but slightly stronger than the others, but on approach- 
ing the distichals it enlarges rapidly, and at the fifth plate it attains the 
proportions of an arm. 
Basals small, forming a short cup; the interbasal sutures deeply notched. 
Radials and costals longer than wide, their upper and lower faces unusually 
narrow; the first costal somewhat longer than the radials, the second a little 
smaller generally. Of the distichals, the ten to twelve lower plates take 
part in the calyx; the three proximal ones being but third smaller than 
the costals; the fourth is considerably shorter, and the succeeding ones 
almost as short as the free brachials. Arms bifurcating (once or oftener), 
long, very slender at their tips; constructed of moderately short, cuneate 
pieces with stout and long pinnules. Interradial and interdistichal areas 
elongate, and composed of an unusually large number of pieces; the former 
