72 



SMITHSONIAN INSTITUTION 



PLATE VIII 

 (All figures natural size unless otherwise stated) page 



Scyphoceinus pratteni (McChesney) 50 



Fig. 1. Left anterior radial view of somewhat compressed specimen, showing the 

 surface characters of the plates, which have pustulose elevations irregu- 

 larly in lower part. The secundibrachs are seen in the ray to the right 

 up to the axillary. Some small knobs along the sutures in the upper 

 left corner may be silicious deposits made during fossilization, which 

 in some cases greatly modify the surface. 

 2a. A small specimen in which the calcareous test has been largely replaced by 

 silica, and much of the original surface destroyed by chemical action, 

 producing an unnatural rugosity of the sculpturing. The specimen is 

 uncompressed, and shows perfectly the characteristic contour of the 

 species. 

 2b. Basal view of same, showing some unweathered plates in which the original 

 smooth surface is preserved ; small spinous pustules are well represented 

 on the lower plates in both views. 



Helderbergian. Hardin County, Tennessee. 



SCYPHOCRINUS MUTABILIS n. Sp 47 



3. A short specimen ; from left anterior radius with surface in natural condi- 



tion, having the turbinate contour of average specimens ; sculpturing 

 in interbrachial regions greatly modified by secondary growth. 



4. A more elongate specimen ; from left anterior radius with lower part of 



calyx less regularly conical ; sculpturing intensified by weathering. 



5. A strongly turbinate specimen ; with surface studded with small knobs upon 



the suture lines perhaps produced by silicious deposits during fossiliza- 

 tion. Lower part restored from other specimens. 



Niagaran to Helderbergian. Hardin, Perry, and 



Benton counties, Tennessee. 



SCYPHOCRINUS PYBURNENSIS n. Sp 52 



60. Abnormal specimen ; lateral view of calyx, showing the fixed pinnules. 

 6b. Basal view, showing 6 plates in the radial circlet ; posterior interradius up. 



The posterior interbrachial passes down to the basal which is truncated 



to meet it, producing an anal area similar to that of the Actinocrinidae. 



Slightly enlarged. 



Helderbergian. Hardin County, Tennessee. 



7. A small specimen, probably of this species, figured for comparison with 



figs. 3a, b, of PI. IX. 



