MONOGRAPH OF THE GENUS GNATHODON, GRAY (RANGIA, 



DESMOULINS). 



[With platf YII.] 



By Wm. H. Dall, 



Honorary Curator of the Department of Molhtsks. 



The genus Gnathodon is oue of those in regard to wliicli much inter- 

 est attaches, ou account of its disputed place in the systems, its uncer- 

 tain nomenclature, and its zoological i^eculiarities. In working up the 

 Tertiary species it became uecessary to review the Avhole group and 

 investigate its relations afresh with newly collected material. Out of 

 these researches, among other results, has grown the present mono- 

 graph, which is believed to settle the systematic position and nomen- 

 clature of the genus. 



Genus GNATHODON, Gray. 



diiathodon (Gray MS.), Sowkrby, Gen. Sli. No. 36, Dec. 1831 (Type G. cuneatus 

 Gray).— Gray, P. Z. S. 1836, p. 101.— Gray, Loudon's Mag. Nat. Hist, i, n. s., 

 p. 376, 1838.— Conrad, Medial Tert. No. 1, p. 23, 1838.— Anton, Verz. Coucb., 

 p. 10, 1839.— Sby, Man. Couch., fig. 83, 1839.— Conrad, Medial Tert., No. 2, p. 

 69, 1840.— SwAiNSOX, Malar., p. 370, 1840.— Conrad, Am. Journ. Sci., xxxviii, 

 p. 92, 1840.— Reeve, Concb. Syst. i, p. 62, pi. 43, 1841.— Conrad, 2d Bull. 

 Nat. Inst., pp. 190, 192, 1842.— Dekay, Moll. N. York, p. 233, 1843.— Hanley, 

 Descr. Cat. Rec. Sb., p. 3."), pi. 10, fig. 22, 1843.— Potiez & Mich., Gal. de 

 Douai, II, p. 194, 1844.— Gray, Gen. Moll. P. Z. 8., 1847, p. 186.— Philii'pi, 

 Haudbucb Coucb., p. 317, 1853.— Woodward, Man., ed. i, ]>. 308, 1856.— Dai.l, 

 Bull. 37, U. S. Nat. Mn.s., p. 62, 1889. 



Jiangia, Desmoulins, Acte.s 8oc. Liu. de Bordeaux, v. No. 25, p. 50, Feb. 15, 

 1832 (Type E. cyrenoides Desm.). — Conrad, Am. Mar. Concb., p. 56, 1833. — 

 H. & A. Adams, Gen. Rec. Moll, ii, p. 380, 1856.— Conrad, Proc. Acad. Nat. 

 Sci., Pbila., 1860, p. 232, 1861.— Conrad, Medial Tert. Index, p. 88, 1861.— 

 Prime, Proc. Bost. Soc. Nat. Hist, vii, p. 347, 1861.— Conrad, Am. Journ. 

 Conch. HI, suppl., p. 30, 1868. — Fi.scher, Man. de Coucbyl., p. 1095, 1887. 



Gnatodon, Rang, Nouv. Ann. du Mnseum, III, p. 217, 1834. 



Columbia (B'lainville MS.), Rang, op. vii., p. 217, 1834. 



Proceedings N.ntion.-il Miisf>iini, Vol. XVTI-No. 988. 



89 



