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BULLETIN No. 2. 



In selecting a complete series of Carboniferous fossils for the 

 State Museum of Natural History, out of the great mass of 

 material brought together in the progress of the geological survey 

 of the State, quite a number of species were found that could 

 not be referred to any of the forms hitherto described, and a part 

 of them are briefly noticed in the following pages. 



The typical specimens that belong to the State collection will 

 be placed on exhibition in the cases of the State Museum, where 

 they will always be accessible for examination and comparison, 

 and they will also be fully illustrated in a subsequent volume of 

 the reports on the geological survey of the State, should the pub- 

 lication of such a volume be authorized by the next General 

 Assembly. 



ORDER CRUSTACEA. 



GENUS COLPOCAKIS, Meek. 



COLPOCARIS CHESTERENSIS. (sp. nOV.) 



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 mar- 

 gin ; ventral margin nearly straight for about two-thirds its length, 

 and then gradually curving upward to the evenly rounded ante- 

 rior extremity. 



The posterior extremity of our specimen is broken away so that 

 its form cannot be clearly determined. 



Length 2f inches ; greatest width, 1 inch. 



Position and locality : From the lower division of the Chester 

 limestone, Chester, 111. 



No. 2496 of the Illinois State collection. 



Collector, A. H. Worthen. 



GENUS SOLENOCAKIS, Meek. 



SOLENOCARIS ST. LUDOVICI. (sp. nOV.) 



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 curving regu- 

 larly upward to the dorsal margin; posterior end terminating in 

 an obtuse point, the ventral margin being more strongly curved 



