36 



nearly twice as wide as long, the lateral sides expand to the 

 superior lateral angles, truncated the entire width above for 

 the support of the second primary radials, from which they 

 are separated externally by a slightly gaping suture. All arc 

 pentagonal. The second primary radials in four of the rays 

 are shorter than the first, pentagonal, axillary, and support on 

 the superior sloping sides the secondary radials. In the ray 

 opposite the azygous area there are four primary radials, tin- 

 second and third are quadrangular, but the third is only about 

 half as large as the second, and the fourth is short, pentagonal, 

 axillary and supports the secondary radials. In the proximal 

 ray on the left of the azygous area and in one of the lateral 

 rays on the same side there are three secondary radials, in 

 the other eight rays there are four secondary radials. The 

 last secondary radials are pentagonal, axillary, and support 

 the tertiary radials. There are only four tertiary radials pre- 

 served in any of the rays in our specimen, and hence our 

 specimen shows only twenty arms in the species. Possibly, 

 the distal series in each ray may divide. 



There are seven plates in the azygous area. The firsl one 

 is pentagonal, rests between the superior sloping sides of two 

 subradials and below the first primary radial on the right. 

 The second truncates a subradial and is heptagonal. The third 

 is heptagonal and abuts the two primary radials and one sec- 

 ondary radial on the right. The fourth is quadrangular, small. 

 and rests on the second. The tilth is the largest plate in the 

 area and rests between the superior lateral sides of the third 

 and fourth plates. The sixth is smaller and rests on the fifth. 



The seventh is a small, triangular plate at the top of the 

 area, between the tertiary primary radials. 



This species is distinguished by the general form, number of 

 primary radials, in the ray opposite the azygous area, number 

 of secondary radials, in the different areas, and by the number 

 of plates in the azygous area. These characters will distinguish 

 the species from all others. 



Found by Dr. M. N. Elrod in the Kaskaskia Group, at 

 Dover Hill, Indiana, and now in the collection of Win. P. E. 

 Gurley. 



