436 PALAEONTOLOGY OF ILLINOIS. 



bases, and again once or oftener further up, the divisions 

 above each bifurcation being about half as large as the 

 main arm below; arm pieces about twice as wide as long, 

 not wedge-shaped, but all showing the downward curvature 

 quite distinctly, and slightly constricted on each side. Sur- 

 face merely finely granular, and the plates of the body 

 neither beveled nor tumid. Column composed of such thin 

 pieces that about fifteen of them may be counted in a length 

 equaling its own thickness near the base. 



Hight of body of the largest specimen to top of first 

 radials, about 0.43 inch; breadth, near 1 inch; thickness of 

 column of same near base, 0.20 inch; diameter of its sub- 

 pentagonal canal, 0.05 inch. 



This Crinoid is so unlike all others known to us, that it is scarcely 

 necessary to compare it with any of the described forms. The specific 

 name is given in honor of Mr. CHARLES WACHSMUTH, the author of 

 the genus, to whom we are indebted for the loan of the typical speci- 

 mens. 



Locality and position Upper Burlington beds of the Lower Carbonif- 

 erous. Burlington, Iowa. Mr. WACHSMUTH'S colectiou. 



KlPTEKOCRINUS AKBOREUS, Wortheil Ms. 



PI. 4, Fig. 8. 



BODY cup-shaped, wider than high, rapidly enlarging to 

 the top of the subradials, and more gently from thence to 

 the top of the first radials. Base small and flat, and mostly 

 covered by the columnar joints. Subradials nearly equal in 

 size, width and hight about equal, and all pentagonal. 

 First radials about twice as wide as high, a little more 

 than twice the size of the subradials, and all pentagonal. 

 The sinus for the succeeding radials occupies about one- 

 half of their width, with their upper margins incurved 011 

 each side of the sinus. Second and third radials nearly 

 equal in size. Fourth radial sharply trigonal in outline, 

 giving support to an arm on each of its upper angles, which 

 bifurcate again on the fourth plate above, on the only ray 

 preserved in the specimen under examination. Plates of 



