INVERTEBRATES. 131 



GENUS SOLENOMYA. Lamarck. 

 SOLENOMYA VARSOViENSis. Worthen. 



PL XIX, Fig. 8. 



Solenomya Varsoriensis, Worthen, March, 1884. Bulletin No. 2 of the Illinois State 

 Museum of Natural History, page 12. 



Shell rather large, elongate-oval or sub-elliptical in outline, 

 moderatety convex, and apparently closed at the extremities. 

 The greatest convexity of the valves is in the umbonal region, 

 and thence obliquely to the ventral margin, and, in front of 

 this elevated region, a slight depression may be seen which ex- 

 tends nearty to the anterior extremity. Beaks depressed and 

 recurved towards the posterior margin, and located a little less 

 than one-third the entire length of the valve behind the an- 

 terior extremity. 



Dorsal and ventral margins nearly straight and sub-parallel, 

 anterior extremity rather narrow, and the posterior broadly 

 rounded. 



Surface of the cast marked by a few obscure wrinkles near 

 the umbo, and lines of growth towards the ventral margin. 



Length about 3 inches; height from the beak to the ventral 

 margin 1% inches; convexity of the valves about 7 / 1Q inch. 



Position and locality; Keokuk limestone, Warsaw, Illinois. 



Collector, A. H. Worthen. 



No. 2539 of the Illinois State Museum. 



SOLENOMYA MONROENSIS. Worthen. 



PI. XVIII, Fig. 5-5a. 



Solenomya Monroensis, Worthen, March, 1884. Bulletin No. 2 of the Illinois State 

 Museum of Natural History, page 13. 



Shell below the medium size, oblong, the length being a little 

 more than twice the height from the beak to the ventral mar- 

 gin; valves moderately convex, the greatest convexity being 

 obliquely along the umbonal slopes from the beaks to the ven- 

 tral margin; cardinal margin straight and about three-fifths 

 the entire length of the valve; basal margin slightly sinuous, 

 from a shallow depression that extends obliquely from the beaks 



