MELOCRINID. 305 
equal, arranged as in Melocrinus. Four of the radials heptagonal, the 
anterior one hexagonal. Costals two; the first hexagonal, the second gen- 
erally pentagonal. Distichals 1X10, all axillary, The first palmar, and 
sometimes the second, takes part in the calyx; the succeeding ones being 
arm plates. Arms long, 
simple, straight, biserial; fringed by good-sized 
pinnules, which are in contact. Interbrachials three or four, but no inter- 
distichals. Structure of ventral disk and anus unknown. Column round; 
tapering. 
Distribution. — The genus is known only from the Oriskany Sandstone of 
Maryland. 
Type of the genus: Technocrinus spinulosus Hall. 
Remarks. — Technocrinus differs from Mariacrinus and Melocrinus in the 
perfect pentamerous symmetry of its dorsal cup, and from the former in havy- 
ing one instead of three to four distichals, no interdistichals, and the arms 
arranged in an almost continuous series around the calyx; while the arms of 
Mariacrinus are arranged in groups. It differs from MJelocrinus in having sim- 
ple arms given off directly from the calyx, and not from its tubular extensions. 
Technocrinus striatus and T. sculptus Hall, were described from detached 
basal plates. 
Technocrinus spinulosus Hatt. 
Plate XXII. Fig. 3. 
1859. Harz; Paleont. New York, Vol. III., p. 140, Plate 85, Figs. 1-18. 
1881. W. and Sp.; Revision Paleocr., Part II., p. 117. 
Calyx subglobose, the arm bases slightly contracting. Plates of the 
dorsal cup marked by a central spine or node, surrounded by smaller 
nodes, which vary in number among the plates. From the nodes two to 
four parallel ridges pass out to the sides, and these are continued upon 
adjoining plates. Near the arm bases the ridges gradually disappear, and 
the plates are marked only by a central spine. 
Basals four, of medium size, forming a shallow basin with five sets of 
four ridges, each set communicating with those upon the radials. Radials 
and costals nearly as wide as long, decreasing in size upwards; the second 
costal but half the size of the first. Distichals one to each side of the cos- 
tal axillaries. The first palmar enclosed in the calyx. Arms twenty, stout, 
rounded ; composed at their bases of cuneate pieces, which interlock farther 
up, and gradually become biserial. Interbrachials apparently four. All 
39 
