DESCRIPTION OF SPECIES 231 



Genus Euchondria Meek 

 Euchondria neglecta (Geinitz) 



1866 Pecten neglectus. Geinitz, Die Garb, und Dyas in Nebr., p. 33, Tab. 2, Fig. 17. 



Nebraska City, Nebraska. 

 3872 Aviculopecten neglectus. Meek, U. S. Geol. Surv. Nebr., p. 193, PI. 9, Figs, la, b. 



Upper Coal Measures: Nebraska City, Nebraska. 



Coal Measures: Illinois. 



Meek's description. "Shell very small, broad subovate exclusive 

 of ears, even thin, rather compressed; sides and base more or less regu- 

 larly rounded; cardinal margin shorter than breadth of the valves. 

 Left valve (according to Professor Geinitz' figure) with ears nearly 

 equal, the anterior one separated from the margin below by a broad, 

 very shallow sinus, and forming less than a right angle at its extremity; 

 posterior ear extending farther down the margin than the other, very 

 faintly sinuous behind, and forming an angle of about 100 degrees at 

 the extremity. Right valve with anterior ear narrow and rather acutely 

 angular, defined by a deep, narrow sinus, extending back about half its 

 length; posterior ear of about the same length, but of greater vertical 

 breadth than the other, rather pointed at the extremity and defined 

 by a moderately deep, broadly rounded sinus, and a subangular umbonal 

 slope. Surface of the body part of both valves apparently only marked 

 by fine concentric striae; ears with a few radiating costae, crossed by 

 fine striae and a few coarser marks of growth. 



"Height and breadth each, 0.26 inch; length of hinge, 0.21 inch." 



Remarks. A single, well preserved specimen was found in the 

 Lowellville limestone, but the species occurs rather commonly in the 

 Lower Mercer and Me Arthur members. The Ohio specimens are on 

 the average larger than those figured by Meek but in other respects 

 the forms are identical. The measurements of the individual from the 

 Lowellville limestone, which is among the largest found, are: length 

 9.7 mm., height 9.5 mm., length of hinge line 7 mm. One from the 

 Lower Mercer limestone measures: length and height 5 mm., length of 

 hinge line 4.2 mm. 



Horizon and locality. Lowellville member: Muskingum County, 

 Locality 19, r. Lower Mercer limestone: Muskingum County, Locali- 

 ties 39 (r), 28 (c), 43 (c), 45 (c); Licking County, Localities 46 (r), 47 (c), 

 48 (r), 49 (r). Upper Mercer: Perry County, Locality 62, r. Black 

 Flint: Jackson County, Locality 87, r. 



