54 



tration, rather larger than they should be, but if so it is very 

 little. 



The first interradial is a large ten-sided plate, quite as large 

 as the second and third primary radials together, and slightly 

 longer than wide. It is followed by two long narrow plates 

 that extend to the top of the third tertiary radials. The inter- 

 secondary radials are single, truncate the third primary radials, 

 have the form of the two small interradials when united, but 

 smaller than the two together. The solid interbrachials are 

 rather thick below and gradually become thinner in their up- 

 ward extension and unite at the summit, with each other and 

 with the small plates that surround the orifice. 



This species is distinguished from others by its general form, 

 and when compared with E. crassus, which it may be said to 

 most resemble, the calyx is proportionally much shorter, and 

 more uniformly rounded and bowl-like, and the tertiary and 

 secondary radials are wholly different in form and in position. 



Found by Prof. A. H. Worthen, in the Niagara Group, in 

 Wayne county, Tennessee, and now in the State Museum, at 

 Springfield, Illinois. The specific name is in memory of the late 

 distinguished State Geologist of Illinois. 



