INVEBTEBEATES. 527 



the first anal piece. All the body plates are depressed at the angles, 

 giving it a pentalobate character somewhat like Barycrinns pentagonus 

 of the Keokuk limestone. 

 Position and locality : LaSalle, Illinois; Upper Coal Measures. 



Genus ETJPACHYCKimJS, Meek and Worthen. 



Etjpachycrinus Craig-ii, Worthen. 



PI. 32, Fig. 1. 



Body subhemispherical below the summit of the first radial pieces, 

 composed of rather thick smooth plates, with a moderately deep con- 

 cavity on the uuder side. ' Basal plates small and concealed in thebasal 

 depression ; subradials rather large, the form of some of them not 

 shown in our specimen from its slightly distorted condition, but four of 

 them are probably hexagonal and one beptagonal, with their superior 

 angles projecting upwards about two-thirds the length of the first radial 

 pieces, and strongly incurved below. First radials twice as wide as 

 high, pentagonal, and beveled on their upper margins so as to leave a 

 well defined suture between them and the second radial pieces. Second 

 radials as wide as the first below, but gradually narrowing upwards, 

 and produced laterally into short stout spines, and supporting on their 

 upper truncated margins two stout brachial pieces that give origin to 

 two arms to each ray. Arms commencing with a single series, but 

 changing on the second or third piece to a double series of rather short 

 stout interlocking pieces, that are at first more than twice as wide as 

 high, but gradually diminishing in width towards their upper extremi- 

 ties. One very small anal piece only is partly visible. Column unknown. 



The basal portion of this species might be mistaken for Shumard's 

 Scajjih. ? hemisphericus, but it differs from that in its more massive body 

 plates, and the more triangular form of the upper portion of its sub- 

 radials. From Eupacli. Fayettensis it may be distinguished by its larger 

 size, more robust form and less convex body plates. 



Position and locality : Vandalia coal shaft, from a bed of black argil- 

 laceous shaly limestone at the depth of about 230 feet, and probably 

 near the horizon of No. 10 coal. 



Dedicated to Mr. E. M. Craig, of Vandalia, to whom I am indebted 

 for the use of the unique specimen figured. 



