INVERTEBRATES. 153 



ORDER CRUSTACEA. 



GENUS COLPOCARIS. Meek. 

 COLPOTARIS CHESTERENSIS. Worthen. 



PI. XXVIII, Fig. 2. 



arii* chesterentis, Worthen, March, 1884. Bulletin No. 2 of the Illinois State 

 Museum of Natural History, page 3. 



Carapace valves, large, elongate, ovate in outline, more than 

 twice as long as high, the widest portion being about the 

 middle: broadly and evenly curved from end to end on the 

 dorsal margin: ventral margin nearly straight for about two- 

 thirds its length, and then gradually curving upward to the 

 evenly rounded anterior extremity. 



The posterior extremity of our specimen is broken away so 

 that it.s form cannot be clearly determined. 



Length 2\ indies: givatest width. 1 inch. 



Position and locality: From the lower division of the Chester 

 limestone. Chester. Illinois. 



Collector. A. H. Worthen. 



No. 2496 of the Illinois State Museum, 



SOLKXHCAKIS. Meek. 



ENOCABIti >\M TI-I.l Uoviri. Worthen. 

 PL XXVIII, Fig. 3. 



<<. Ludorici. Worthen. March, 1881. Bulletin No. 2 of the Illinois State 

 Museum of Natural History, page. 



Carapace valves narrow and elongated, the length being equal 



to about three times the height, probably slightly convex 



though flattened on the surface of the limestone: dorsal and 



ventral margins nearly straight and parallel: anterior end 



19 



