442 MISSISSIPPIAN BRACHIOPODA 



of Acambona, if these two genera should prove to be distinct. It differs 

 from all other species of Eumetria in its more narrowly ovate outline, and in 

 its exceedingly fine radiating plications. In these characters it much 

 more closely resembles Acambona prima, indeed, in all essential features it 

 has every appearance of being a diminutive example of that species, and 

 it should perhaps be so considered. The satisfactory interpretation of 

 these rare forms, however, must be deferred until more abundant mate- 

 rial is available for study. 



Horizon. Lower Burlington white chert. 



EUMETRIA VERNEUILANA (Hall) 

 Plate LXXVI, Figs. 18-24 



1852. Terebratula serpentaria 1 Owen, Geol. Rep. Wis., Iowa and Minn., 



tab. 3A, fig. 13. 



1856. Retzia Verneuilana Hall, Trans. Albany Inst., vol. 4, p. 9. 

 1858. Retzia verneuilana Hall, Geol. Iowa, vol. 1, pt. 2, p. 657, pi. 23, 



figs. la-d. 



1882. Eumetria Verneuilana Whitfield, Bull. Am. Mus. Nat. Hist., vol. 



1, p. 50, pi. 6, figs. 28-30. 



1883. Eumetria verneuiliana Hall, 12th Rep. Geol. Surv. Ind., p. 335, pi. 



29, figs. 28-30. 



1884. Retzia Verneuiliana Walcott, Pal. Eureka Dist., p. 220, pi. 7, figs. 



5-5a. 

 1894. Eumetria Verneuiliana Hall and Clarke, Int. to Study of Brach., pt. 



2, pi. 37, figs. 1-4, 6, 10. 



1894. Retzia verneuiliana Keyes, Mo. Geol. Surv., vol. 5, p. 95. 



1895. Eumetria Verneuiliana Hall and Clarke, Pal. N. Y., vol. 8, pt. 2, 



pi. 51, figs. 13-26, 34, 35 ; pi. 83, figs. 26-27. 

 1897. Eumetria verneuilana Weller, Trans. N. Y. Acad. Sci., vol. 16, 



p. 259. 

 1899. Eumetria verneuiliana Girty, Mon. U. S. Geol. Survey, vol. 32, p. 



560, pi. 68, figs. 12a-b. 



1903. Eumetria marcyi? Girty, U. S. Geol. Survey, Prof. Paper, No. 16, p 



303. 



1904. Eumetria marcyi Girty, Prof. Paper U. S. Geol. Survey, No. 21, p. 



49, pi. 10, figs. 15-17. 

 1906. Eumetria marceyi Beede, 30th Ann. Rep. Geol. Surv. Ind., p. 1319, 



pi. 22, figs. 28-30. 

 1911. Eumetria marcyi Girty, Bull. U. S. Geol. Survey, No. 439, p. 77, 



pi. 8, fig. 10. 

 1911. Eumetria marcyi Morse, Proc. Ohio State Acad. Sci., vol. 5, p. 386, 



fig. 14. 



Description. Shell small, longer than wide, the greatest width near the 

 mid-length of the shell, ovate in outline, the lateral margins diverging 

 from the beak at varying angles in nearly straight lines or with slightly 

 convex curvature to the line of greatest width of the shell, in front of 

 this line the outline is subsemicircular with sometimes a slight straighten- 

 ing or truncation of the margin at the anterior extremity, the hinge-line 



