492 



PALEONTOLOGY OF ILLINOIS. 



*r?$WW? T Prr'. 



Mmkmk 



View of calice. 



I am indebted to Dr. Oliver Everett, of Dixon, for the very fine spe- 

 cimen from which the above figures and description were drawn. For the 

 opportunity of comparing this with a typical form of Cnemidium, from 

 the Upper Jurassic formation of Wurtemberg, in Bavaria, I am indebted 

 to Dr. C. Eomikger, State Geologist of Michigan. 



ECHINODEHMATA. 



GrEmrs HOMOCEINUS, Hall. 



HOJIOCRINTJS AiN'GUSTATTJS. M. and W. 



PI. 23, Fig. 8. 

 Homocrvnus anqustatus, Meek and Worthed, 1870 ; Proceed. Acad. If at. Sci., Philad., p. 30. 



Body below the first radial pieces more or less obconic, or somewhat 

 constricted below the middle. Base forming a narrow cup, sometimes 

 nearly as high as wide, with vertical sides; composed of convex pieces, 

 once and a half to nearly twice as wide as high. Subradial pieces as 

 long as the basals, or sometimes a little longer, and always wider; more 

 or less couvex, all hexagonal excepting one on the anal side, which is 



