66 SMITHSONIAN INSTITUTION 



PLATE V 

 Stem characters 

 (All figures natural size unless otherwise stated) page 



Scyphocrinus elegans Zenker 30 



Cape Girardeau, Missouri 

 Fig. 1. A free calyx to the height of about IIBr 12 , radial view; showing character- 

 istic surface or ornament ; used partly in construction of figures of 

 PI. IV. Note the change of direction in the rami at the fifth IIBr. 

 2a, b, c. a, Cross-section of column proximal to calyx (12 mm. diameter, 13 

 joints to the cm.) ; showing the extremely wide axial canal (lumen) 

 and the short alternating columnals. X 2. 



b, Joint-face of same, showing pentagonal outline of lumen, and 

 contact area forming the rim of the intercolumnal chamber (ligament 

 fossa) bordering it, with the radiating crenulse traversing both, x 2. 



c. Oblique view of same joint-face, further enlarged, with vertical 

 section ; to show the small remaining points of stellate lumen at angles 

 of the pentagon, and the relative thickness of the columnal from the 

 periphery to the flange-like part extending inward as a diaphragm 

 between the chambers. X 8. 



30, b, c. Similar views of section at median part of column (8 mm. diameter, 

 8 joints to the cm.) ; showing much narrower lumen, with stellate 

 radiations in the part of the columnal forming the diaphragm. 

 Figs, a and b X 2 ; c X 6. 



4a, b. Similar views of section near distal end of stem (6.5 mm. diameter, 

 5 joints to the cm.) ; showing smaller stellate lumen, with thicker 

 diaphragm. X 6. 



5. Oblique view with vertical section of columnal of intermediate type toward 



the distal end, having relatively narrow chamber and small stellate 

 lumen, x 6. 



Scyphocrinus ulrichi (Schuchert) 54 



6. Distal end of stem with branches merging into a plated area within the 



collar (broken away), being the upper part of a large bulb (not 

 included in figure) ; showing the small stellate lumen, and position of 

 large openings at bifurcations, leading to the chambers. U. S. National 

 Museum. 



Helderbergian. Dougherty, Oklahoma. 



Ancyrocrinus bulbosus Hall 10 



7. 8. Different forms of anchor-like distal end of the stem, with its four 



grapnels. 

 9. Proximal view of another specimen showing the quadripartite stem lumen. 

 10. A transversely fractured specimen showing how the stem extends to the 

 bottom of the terminal structure. 



Hamilton Group ; Middle Devonian. Clark County, Indiana. 



