SMITHSONIAJN INSTITUTION 
198 
PLATE 13 
(Figures natural size unless otherwise stated) 
Marsipocrinus rosaeformis (Troost) 
Figs. I, ia,ib,ic. A typical hemispheric calyx, with surface characters finely preserved: i. Lateral 
view, showing the great prominence of the arched tegmen over the flat dorsal cup ; 
radial facets directed below the horizontal, iBr heptagonal, their distal margin pro- 
jecting, with a strong lip, and corrugated, id. Dorsal side, with extremely sharp 
sculpturing in form of wrinkles radiating upon the plates and meeting in slightly 
raised ridges running from the angles, dividing the surface into triangles ; very small 
axillary IBr, the much larger IIBr resting on distal face of RR ; low rim around 
the lumen, ib. Detail of these structures enlarged, showing more fully the succession 
of brachials leading to the biserial arm. X 2. ir. The tegmen, showing complete dis- 
tribution of orals and other plates strongly nodose; iAmb connecting with the arched 
iBr and bearing numerous small and distinct tubercles; ambulacra defined but not 
conspicuous. 
2, 2a, 2b, 2c. Similar views of a specimen with concavo-convex calyx ; radial facets pointing 
strongly downward; surface ornament of much smaller wrinkles. 2b is enlarged. X 2. 
3' 30, zb, 3c. A smaller specimen with more granular ornamentation ; similar views, zb 
enlarged. X 2. 
4, 4a, 4b. Similar and larger specimen with highly sculptured tegmen and base finely granular. 
5, su. A specimen of this type with more convex base than the preceding ; iBr extremely 
prominent. 
6, 6a, 6b. Specimen with tegmen strongly nodose. 
7, 7a. Specimen with tegmen plates more angular than nodose. 
8, 8a. A very mature specimen, with faint granulose-striate markings on dorsal cup, and teg- 
men plates profusely covered with small nodes; ambulacra inconspicuous. 
Beech River formation; Decatur County, Tennessee. 
