120 PALJEONTOLOGY OF NEW YORK. 



more like those ofEumeiria Vemeuiliana, Hall. The hinge-plate bears two short 

 processes on its posterior edge, which extend only for a short distance into the 

 umbonal cavity ; this organ is very imperfectly known, but as far as under- 

 stood it seems to be nearer in structure to that of Hustedia than of Eumetria. 

 Acambona prima was described from the lower beds of the Burlington 

 limestone, and it is quite probably identical with the species described by 

 Professor Swallow, at an earlier date, as Retzia Osagmsis, from the Choteau 

 limestone. 



. Genus HUSTEDIA,* gen. nov. 



PLATE IJ. 



1868. Terebratula, Marcoo. Geology of North America, p. 51, pi. vi, fig. 11. 



1859. Retxia, Mbbk and Hatdbn. Pi-oc. Acad. Nat. Sci. Philadeli)hia, vol. iii, second ser., f. 27. 



1860. Retzia, McChksnby. New Palaeozoic Fossils, p. 45. 



1866. Relzia, Gbinitz. Carbon iind Dyas in Nebraska, p. 39, pi. iii, fig. 6. 



1868. Relzia, McChbsnby. Trans. Chi<rago Acad. Sciences, vol. i, p. 32, pi. i, fig. 1. 



1872. Retzia, Mbbk. Hayden's U. 8. Geol. Survey Nebraska, p. 181, pi. i, fig. 13 j pi. v, fig. 7. 



1874. Eumetria, Dkrbt. Bull. Coi-nell University, vol. i, p. 4, pi. viii, figs. 4, 6, 7, 8, 10 ; pi. iz, fig. 3. 



1875. Terebratula, Mabcou. Trans. St. Louis Acad. Sci., vol. iii, p. 252. 



1875. Retzia, White. Wheeler's Geogr. Surveys West of 100th Meridian, vol. iv, pp. 141, pi. x, fig. 7. 



1883. Eumetria, Waauex. PaliBontologia Indica, ser. xiii, vol. iv, p. 487. 



1884. Retzia, Walcxht. Monogiv U. S. Geol. Survey, vol. viii, p. 220, pi. vii, fig. 5. 



1884. Relzia, White. Thirteenth Ann. Rept. State Geologist Indiana, p. 136, pi. xxxv, figs. 10-12. 



In external characters the shells constituting this genus are indistin- 

 guishable from those of Eumetria, except in their much coarser plication. 

 For this reason they have been classed under the latter genus by several 

 writers, though the internal structure in the two groups is curiously distinct. 

 While the complicated structure of the interior in Eumetria was not under- 

 stood such an association of the species was altogether natural. The type of this 

 new genus the Terebratula Mormoni, Marcou (= Retzia punctulifera, Shumard), — 

 a characteristic species of the upper Coal Measures in both North and South 

 America. The essential difference of this species from Eumetria vera lies in the 



• To the memory of the Honorable Jambs William Hustbd, this interesting and widely distributed genus 

 of Bracbiopods is dedicated. A patron and promoter of science, who, during a i>ei-iod of more than twenty 

 years, as Rejircsentativc in the Assembly of the Legislature of New York, zealously espoused the interests 

 of the Paleontology, and of eveiy other department of the Natural History of the State of New York. 

 A wise legislator and educator, a faithful and unswerving fnend and counsellor of many years, his name 

 deMrves to be spoken with respect and reverence wherever geologic science shall be taught or studied, 

 throughout the civilized world. 



