PROCEEDINGS OF THE UNITED STATES NATIONAL MUSEUM 



issued ImJ^vvA, *Q^j^] hy the 



SMITHSONIAN INSTITUTION 

 U. S. NATIONAL MUSEUM 



Vol. 89 Washington: 1941 No. 3103 



DIXOTOCRINUS, A NEW FOSSIL INADUNATE CRINOID 



GENUS 



Bv Edwin Kirk 



The new crinoid genus here described conies from the lower 

 Chester group of Alabama and the Chester of Illinois (Mississip- 

 pian). It is distinctive but has a limited known geographic and 

 stratigraphic range. One new species and two described species are 

 referred to the genus, 



DINOTOCRINUS, new genus 



Genotype. — Dinotocrhms co<)i} pactn-s.^ new species. 

 Generic diagnosis. — 



Crown. Compact, subcylindrical, expanding slightly to about one- 

 half its height, then contracting slightly. Ratio of dorsal cup 

 to height of crown about 1 : 10. 



Dorsal cup. Cyathiform, with sharply truncated base. 



IBB. Small, fused into a flat, pentagonal plate entirely contained 

 within the basal depression. 



BB. Large, forming the base of the cu|) as seen in side view, 



RR. Wider than high, large. Facet full width of R, linear. Suture 

 slightly gapiug. 



IBr. One in each ray. Variable in height; those in r and 1 post 

 and ant RR tending to be higher than those in r and 1 ant RR. 

 Upper sloping faces of lAx long. 



513 



274412—41 



