39 



doubtfully to Phillip's species, M. lingualis from the carboniferous 

 limestone of Yorkshire, G. B. Having become satisfied that it is 

 specifically distinct from Phillip's species, I now propose for it the 

 name of Litfiophaga Illinoiensis. 



CAMEEOPHOEIA GIFFORDI, N. SP. 



Shell above the medium size, broadly ovate or sub-circular in 

 general outline. Dorsal valve nearly circular, moderately convex, 

 the greatest convexity being about one-third the distance from the 

 beak to the front part of the shell, umbo depressed. Ventral valve 

 much more convex, and the beak produced beyond that of the dorsal 

 valve, and strongly recurved. 



The only specimen we have seen of this fine sliell is an internal 

 cast, with a fragment of the test adhering to the beaks. Traces of 

 ten or twelve broad, shallow plications can be seen on the front por- 

 tion of the shell, two or three of which probably extended to the beak 

 on the ventral valve, while the others became obsolete before reach- 

 ing the cardinal border. Traces of fine longitudinal striations are 

 also visible with a good glass. Length from the beak to the front 

 23, breadth 22, height 14 millimeters. 



Dedicated to the memory of Mr. Wm. Gifford, of Peoria county, 

 111., from whom the specimen was received. 



Position and locality. Middle coal measures near Alta, Peoria 

 county. 111. 



Illinois State collection. 



CHjENOMYA MARIA. N. SP. 



Shell elongate, sub-cylindrical, anterior side much compressed and 

 aperture entirely closed ; posterior side truncated and widely gaping. 

 Base slightly convex in outline, rounding up gradually in front and 

 abruptly behind, dorsal side a little concave from the beaks to the 

 posterior extremity. Beaks depressed, incurved, and located about 

 one-fifth the entire length of the shell from the anterior side. 



Two conspicuous furrows commence at the beak, the anterior one 

 crossing the valve obliquely to the base of the shell at a point about 

 two-fifths of its entire length from the anterior side ; the posterior 

 one crossing the shell much more obliquely, and terminating at the 

 base of the shell, near its posterior extremity. 



In addition to these furrows each valve is marked by about thirty- 

 two longitudinal ridges that are a little wider than the spaces 

 between them. These commence at the dorsal margin near the 

 beak, and when they cross the posterior furrow already described, 

 they are deflected abruptly forward to a right angle with their former 

 course, about two out of every three ending at the anterior furrow, 

 while the others are continuous across that to the anterior border of 

 the shell. 



A small fragment of the shell, attached to the cast, shows that 

 the surface was finely striated obliquely from the beak to the front, 



