Bkkde.] Carboniferous Invertebrates. 91 



by a proportionally shorter foramen. Surface of both valves 

 ornamented with concentric marks of growth and fine radiat- 

 ing crowded striae, which increase mainly by intercalation, and, 

 as in many other species of the genus, show occasional perfora- 

 tions toward the front, apparently left by the removal of very 

 small tubular spines." ''Length of a well-developed gibbous 

 specimen, rather above medium size: .38 inch; breadth, .43 

 inch ; convexity, .27 inch." 



Range and distribution : Upper and Lower Coal Measures ; 

 Fort Scott, Kansas City, Eudora, Lawrence, Lecompton. 



ENTELETES. 



de Waldheim, Oryct. Gouv. Moscou, p. 193, tab. XXVI, tf. 6, 7. 

 Waagen, Pal. Indica, ser. xiii, I, p. 550, (1884) ; etc. 



Enteletes hemiplicata. Plate XII, figs. 6, 6b. 



Spirifer hemipJiaata Hall, Stansbury's Expl. Gt. Salt Lake, p. 409, pi. 



iv/f. 3, (1852). 

 JihynchoneUa anqulata Geinitz (nonLinne*), Carb. u. Dyas in Neb., p. 37, 



pi. in, ff. 1-4, (1866). 

 Sifntri* lasma hemiplicata Meek and Worthen, Geol. Surv. 111., n, p. 323, 

 1 f. 36, p. 324, f. 37, (1866); Meek, Fin. Rep. U. S. Geol. Surv. Neb., p. 177, 



pi. vi, f. 1, pi. vin, f. 12, (1872); etc. 



Meek's description : " Shell in young examples only moder- 

 ately convex, and having all the external appearances of a true 

 Orthw; in adult specimens, often globose, or even more con- 

 vex than long or wide. Hinge line very short, or not more 

 than one-third the greatest breadth of the valves, and, owing to 

 the gibbosity of the shell, imparting little or no angularity to 

 the outline of the lateral slopes. Dorsal valve more convex 

 than the other, and very strongly arched, particularly in ma- 

 ture shells; umbonal region gibbous, and often, in adult ex- 

 amples, projecting somewhat beyond the beak of the other 

 valve; beak strongly incurved, so as to bring its apex under 

 the beak, and nearly against the area of the other valve ; area 

 rather narrow, and distinctly incurved with the beak. Ventral 

 valve convex, beak moderately prominent, and arched or more 

 or less incurved; area triangular, small, about one-third as 

 high as wide, and moderately well defined ; its triangular fora- 

 men scarcely as wide as high. Surface of both valves orna- 

 mented with rather fine, regular, crowded, radiating striae, and 



