728 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
Eucladocrinus tuberosus (Hatt). 
Plate LX XII. Figs. 5, 4 a, 0, ¢. 
a r 
1858. Platyerinus tuberosus — Hai; Geol. Rep. Iowa, Vol. I., Part II., p. 534, Plate 8, Figs. 7a, 0. 
1881. Platycrinus tuberosus — W. and Sv.; Revision, Part II., p. 76 (Proc. Acad. Nat Sci. Phil., p. 250). 
Syn. Platycrinus occidentalis 8. A. Minin, 1891; Geol. Surv. Missouri, Bull. 4, p. 10, Plate 1, 
Figs. 5, 6. 
se 
2 ——SES SSS 
Hy Calyx wider than high, hemispheric to subpyramidal, slightly pentangular 
| in outline. Dorsal cup discoid and very short, resting on the projecting 
| margins of the radial facets ; the lower edges of the facets directed slightly 
iae downward, the limbs bending upward at a right angle. Ventral disk some- 
ry what bulging at the posterior side, and portions of the interambulacral 
plates visible from a dorsal aspect. Plates thin, without ornamentation, and 
san very little elevated ; the sutures slightly grooved. This species, in the form 
ct | of its brachial trunks, of which there is but one to the ray, and in the 
arrangement of its arms, which are extremely short and given off in clusters 
aa from the sides of the trunks, resembles certain species of Onychocrinus. 
Basal disk proportionally small, with a small depression in the middle for 
the proximal column joint. Interbasal sutures obsolete. Radials subhex- 
agonal, lying horizontally to near the facets, where they are twice as wide as 
iy | aaa | at the bottom. ‘The facets occupy less than half the width of the plates; 
| they are semi-elliptical, greatly projecting, directed more or less obliquely 
downward; they are deeper excavated in the middle, and the margin is | 
Sy || obscurely striated. Calycime appendages heavy but short, their transverse 
section oblong. They are directed obliquely downward to their full length, 
and are composed of five successive orders of brachials, which give off arms 
from the outer sides. The different orders, except the costals, consist of two 
plates each, and are roofed by two series of rigid, very large covering pieces. 
| Costals extremely large, reaching a length of 6 to 7mm.; they are rounded 
eh | : on the back, the sides abruptly curving inward, and the distal faces, although 
axillary, almost straight. Distichals 2 x 2, a little wider than long and 
quadrangular; the second pentangular and irregularly axillary. The latter 
plates give off 2 X 2 X 2 palmars, of which the outer ones support a cluster 
oe 
er oe 
3308 
a oe | of arms; while the inner ones take part in the calycine appendages. The 
. lower plates of the outer series are trigonal, and rest upon the sloping upper 
faces of the distichals and against the sloping lower faces of the inner palmars 
