594 PALEONTOLOGY OF ILLINOIS. 



also about the middle, giving a sinuous outline to its upper 

 margin. Surface smooth, but showing under the lens ob- 

 scure lines of growth. 



Position and locality Lower Coal Measures, roof of the Alton coal 

 seam ; Alton, Illinois. 



MACROCHEILUS NEWBERRYI, Stevens sp. 



PL 28, Fig. 14. 



' 

 Loxonema Newberryi, STKVEXS. Am. Jour. Sci., Vol. 25, n. s., p. 259. 



Position and locality Roof of Danville coal ; Danville, Vermilion 

 county, Illinois. 



Genus ACT^CXNINA, D'Orbigny. 



ACT^EONINA MINUTA, SteveilS Sp. 



PL 29, Fig. 2*. 

 Loxonema mimtta, STEVENS. Am. Jour, of Sci., 1858, Vol. 25, n. s., p. 260. 



Position and locality Eoof of Danville coal ; Danville, Illinois. 



Genus PLATYCERAS, Conrad. 



PLATYCERAS SPINIGERUM, Worthen Ms. 



PL 28, Fig. 4. 



SHELL rather small, elongate oval in outline, strongly 

 recurred, apex pointed, and slightly twisted to the left 

 (when looking at the shell with the apex behind), aperture 

 ovate, with sinuous depressions extending from the aper- 

 ture nearly to the apex, crossed by transverse marks of 

 growth, giving a rugose appearance to the surface. Right 

 hand side of the shell, as seen with the apex behind, de- 

 pressed, or concave; the opposite side convex, and bearing 

 the bases of several small, scattering spines, extending up 

 about two-thirds the distance to the apex. 



