REVISION OF PALEOZOIC STELLEROIDEA. 299 



Fig. 5. — Urasterella pulchclla (Billings) (also see plate 28). 



Camera lucida drawing X 8. The large plates to the left are the coin- 

 shaped adambulacrals (some have tipped over and show their articular 

 faces), next are the small elongate inframarginals, and outside of these 

 are the spinose ambitals. 



Figs. 6 and 7. — Urasterella ulrichi, new species (also see plate 29). 



6. Camera lucida drawing X 4 of the abactinal side of a young 

 individual. The medial ray plates should be more tumid than here 

 represented. Note the primitive structure of the disk. 



7. Camera lucida drawing X 6 of the actinal side of a young indi- 

 vidual. The outer dark margin is adhering rock, through which some 

 of the abactinal ambital nonarticulating spines project. Note the 

 phanerozonian interbrachial characters. 



Middle Ordovicic (Black River). Minneapolis, Minnesota. 



Ulrich collection of the United States National Museum (Cat. 



No. 60612). 



Plate 31. 



Figs. 1 and 2. — Compsaster formosus Wortheu and Miller. 



1. Actinal view, natural size, of the holotype. Reproduction of the 

 original illustration. 



2. Part of a ray, X 2. After Worthen and Miller. 

 Upper Mississippic (Chester). Okaw Bluffs, Illinois. 

 "Illinois State collection of 1880, No. 2476." 



Fig. 3. — Calliasterella viira (Trautschold). 



Reproduction, natural size, of Schondorf's reconstruction. 



Upper Carboniferous (Moscovian). Mjatschkowa, near Moscow, Russia. 



Plate 32. 

 Fig. 1. — Stenaster Salter i Billings. 



Retouched photograph X 3 of a cotype. Actinal view. 



Mddle Ordovicic (Trenton). Belleville, Ontario, Canada. 



Collection of the Geological Survey of Canada. 

 Fig. 2. — Schuchertia stellata (Billings) (also see plate 33). 



Photograph X 4 of the actinal side of the holotype. 



Middle Ordovicic (Trenton). Ottawa, Canada. 



Collection of the Geological Survey of Canada (No. 1399). 

 Fig. 3. — Schuchertia laxata, new species (also see plate 33). 



Retouched photograph X 2 of the holotype from the abactinal side. 



Upper Ordovicic (Richmondian). Waynesville, Ohio. 



Harris collection of the United States National Museum (Cat. No. 60613). 

 Figs. 4 and 6. — Schcenastcr (?) legrandensis Miller and Gurley. 



4-5. Actinal and abactinal views, natural size. 



6. Part of actinal side X 6.5. After Miller and Gurley. 



Lower Mississippic (Kinderhookian). Le Grand, Iowa. 



?Gurley collection of the University of Chicago. 



Plate 33. 



Fig. 1. — Schuchertia stellata (Billings) (also see plate 32). 



Camera lucida drawing X 8 of the abactinal surface. Somewhat 

 restored. 



Middle Ordovicic (Trenton). Near New Edinburgh, Canada. 



Collection of the Geological Survey of Canada. 

 Figs. 2 and 3. — Schuchertia laxata, new species (also see plate 32). 



2. Some of the outer ambital plates, all disjointed, X 8. 



3. An interbrachial area and ambulacrum, X 4. 

 Upper Ordovicic (Richmondian). Waynesville, Ohio. 



Harris collection of the United States National Museum (Cat. No. 

 60613). 



