27 



facet, where small nodes are made to terminate the sculptured 

 ridges. First radials highert han wide, tw oheptagonal and two 

 hexagonal and one pentagonal, central tubercle transverse and 

 sending two ridges to the basal plates and one to each of the 

 other adjacent plates. Second radials hexagonal, wider than 

 high, a little smaller than the first radials, central tubercle only 

 slightly elongated transversely, from which a ridge is directed 

 to each adjoining plate. Third radials a little smaller than the 

 second, wider than high, hexagonal, and bearing on the upper 

 lateral sides a single secondary radial. Secondary radials smaller 

 than the third primary radials and supporting on one of the 

 upper sloping sides a single tertiary radial and on the other a 

 series of three or more tertiary radials, before the arm becomes 

 free; the exact number cannot be determined from our speci- 

 men. The single tertiary radials bear an axillary plate of the 

 fourth order, which supports, on each upper sloping side, two 

 or more plates before the arms becomes free. There are, there- 

 fore, at least twelve arms in each radial series or sixty arm 

 openings to the vault in this species. 



First regular interradial hexagonal, as large as the second 

 primary radials, sculptured in the same way, and supporting- 

 two smaller but similar plates in the second range. The latter 

 are followed by two smaller plates and these by one still smaller 

 plate, which gives us six plates in each regular interradial area. 

 There is one plate in each intersecondary radial area that rests 

 on the third primary radial. There are nine plates in the azy- 

 gous area. The first one is in line with the first radials, of the 

 same size and sculptured in like manner. It is followed by three 

 plates in the second range and these in turn by three smaller 

 plates, above which there are two still smaller plates before the 

 tertiary radials unite to cut off the azygous area from the plates 

 of the vault. 



The sculpturing on the plates in this species is similar to that 

 on Strotocrinus ectypus, but otherwise it bears little resemblance 

 to that species. It is so different in the form of the calyx and 

 number of the interradials from S. regalis and kindred species 

 that no comparison with any of them is necessary to distin- 

 guish it. 



Found in the Burlington Group, at Burlington, Iowa, and 

 now in the Illinois State Museum, at Springfield. 



