404 PALEONTOLOGY OF ILLINOIS. 



on the third piece in two of the rays seen, and on the 

 fourth in another, the pieces being rounded, nearly as wide 

 as long, somewhat constricted in the middle, and a liftle 

 dilated at their upper ends, while all of the axillary pieces 

 at the various bifurcations have much the same form as 

 the last free radials. Beyond the first bifurcations men- 

 tioned, above the last free radials, several of the arms are 

 seen to bifurcate again on the fifth piece and twice to three 

 times more at various distances above, while they all gradu- 

 ally decrease in thickness with each bifurcation until they 

 become much attenuated, though the pieces of w^hich they 

 are composed maintain their length to such a degree that 

 those of the smaller divisions are nearly twice as long as 

 wide. 



Surface of body plates slightly beveled at the sutures, 

 and more or less roughened by small ridges or nodes, which 

 on the subradial pieces present the appearance of nearly 

 continuous, radiating, somewhat nodulous ridges, while 

 those of the first radials have more the character of irregu- 

 larly disposed nodes. 



Length of the body below the top of first radial pieces, 

 0.40 inch ; breadth of same about 0.64 inch ; length of arms 

 from their origin on the last radials at least 2 inches, and 

 perhaps a little more. 



This species seems to be more nearly allied to specimens in Mr. 

 WACHSMUTH'S collection that have been identified with Poteriocrinus 

 Barrisi, Hal], than to any other form with which we are acquainted. 

 It differs entirely, however, in its sculpturing, that species having its 

 body plates marked with numerous, rather tine, thread-like, radiating 

 costae. The arms, however, are more similar to those of our species, 

 though they are rather stouter below in the latter. . 



We have not had an opportunity to see the type of Poteriocrinus 

 Barrisi, but the form in Mr. WACHSMUTH'S collection, referred to that 

 species by all the Burlington geologists, is a true Cyathocrinus, or more 

 properly Cyathocrinites. 



Locality and position ^Lower division of the Burlington beds (Lower 

 Carboniferous) at Burlington, Iowa. Mr. WACHSMUTH'S collection. 



