152 



SMITIISONrAN INSTITUTION 



PLATE LXXIII 

 (All figures natural size except where otherwise stated) 



PAGE 



Figs. 1-4. Onychocrinus magnus Worthen 433 



Fig. I. The type, after additional cleaning, exposing the ramules not shown in the original figure; 

 a very mature and somewhat robust specimen. Illinois State Museum, Springfield. 



Monroe County, Illinois. 

 2a. Mature specimen from St. Louis ; posterior view, showing the small anal tube, with bor- 

 dering perisome ; large primary interbrachial followed directly by finely plated peri- 

 some ; the relative size and proportions of rays and their main branches ; and the 

 succession of clusters of ramules. Has 3 IBr in anterior ray. Author's collection. 

 26. Outline in part of left lateral ray, which is less eroded by weathering, showing the arcuate 

 sutures. 



3. Anterior view of another specimen from same locality having but 3 IBr in all the rays. 



4. Lateral view of a less mature specimen from same locality, having no iBr in the second 



axil ; has 3 IBr in one ray. Author's collection. 

 St. Louis Gr. ; Lower Carboniferous. Illinois. 



Figs. 5-8. Onychocrinus distensus Worthen 436 



Figs. 5, 6. Specimens from Huntsville, Alabama, in strata equivalent to the Renault beds of Illinois. 

 In fig. S the ray to the left has 15 clusters of ramules on each ramus, not all visible in 

 this view. Author's collection. 



7. Type of Forbesiocrinus semiovatus M. and W., from Hardin County, Illinois ; a young 



and obscure specimen belonging to Onychocrinus, and perhaps to this species. Uni- 

 versity of Illinois. 



8. Type of O. distensus, from the Renault formation, lower part of the Kaskaskia, Monroe 



County, Illinois. Illinois State Museum, Springfield. 

 Renault formation and its equivalent, lower part of Kaskaskia ; Lower Carbonifer- 

 ous. IlHnois and Alabama. 



