386 FOSSIL TURTLES OK NORTH AMERICA. 



presents itself in Stylemys, viz., a bifurcate penultimate suprapygal. The nearest approach to 

 this is seen in Kachuga (Boulenger, Cat. Chelonians, p. 53, fig. 16). 



The epiplastral lip of Stylemys does not project forward beyond the general border of the 

 plastron, as it does in most of the species of Testudo; yet the epiplastral bones are thickened 

 anteriorly on the upper side in a manner similar to that found in Testudo. 



The geological duration of the genus, so far as known, is from the lower Oreodon beds of 

 the White River deposits to the John Day Miocene. The writer has not been able to find any 

 records of the finding of specimens of the genus in the Titanotherium beds. It is remarkable 

 that the genus Hadrianus should disappear in the Uinta deposits, while Stylemys and Testudo 

 should appear immediately afterwards in the White River beds. 



The writer has elsewhere (Amer. Geologist, xxxv, 1905, p. 342) exprest the opinion that 

 the living North American species included under the name Gopherus (Xerobates Agassiz) 

 have descended, not from Hadrianus, but rather from Stylemys. This opinion is based 

 principally on the fact that the species of both groups have a longitudinal ridge along the 

 midline of the triturating surface of the upper jaw. This idea requires the confirmation to be 

 obtained only in the discovery of more complete skeletons. 



Analysis of Species of Stylemys. 



1. Shell nearly as broad as long. Seldom an octagonal neural present. Pectoral scute, on 



midline, three-tenths width of abdominals; free borders of hinder peripherals acute. . nebrascensis 



2. Shell nearly as broad as long. Second neural octagonal, third quadrangular; pectoral 



scutes one-fifth width of abdominals; hinder peripherals obtuse capax 



3. Shell more elongate; neurals as in capax; peripherals more as in nebrascensis conspecta 



4. Not well known. Third neural 4-sided; anterior lobe truncated in front calaverensis 



Stylemys nebrascensis Leidy. 

 Plate 59, figs. 2-4; plate 62, figs, r, 2; text-figs. 486-496. 



Stylemys nebrascensis, Leidy, Proc. Acad. Nat. Sci. Phila., v, 1 85 1 , p. 172; Ann. kept. U. S. Geol. Surv. 



Wyoming, etc., 1870 (1871), p. 366; Contrib. Kxt. Fauna West. Terrs., 187 3, p. 224. Cope, Trans. 



Amer. Philos. Soc, xiv, p. 124, plate vii, figs. 10-12; Vert. Ten. Form. West, 1884, p. 769; Contrib. 



Canad. Palaeont., ill, 1891, p. 5. Lydekker, Proc. Zool. Soc. Lond., 1889, p. 94. Hay, Bibliog. 



and Cat. Foss. Vert. N. A., 1902, p. 450; Ann. Carnegie Mus., iv, 1906 (1907), p. 19, figs. 9-1 1. 

 Emys hemispherica, Leidy, Proc. Acad. Nat. Sci. Phila., v, 1851, p. 172; 6th Ann. Rept. Smithson. 



Inst., 1 851 (1852), p. 65. 

 Testudo lata, Leidy, Proc. Acad. Nat. Sci. Phila., v, 1851, p. 172; 6th Ann. Rept. Smithson. Inst. 1851 



(1852), p. 65; Owen's Rept. on Geol. Surv. Wis., Iowa, and Minn., 1852, p. 572; Ancient Fauna 



Nebraska, in Smithson. Contrib. Knowl., VI, 1854, art. vii, pp. no, 115, plate xxiii, figs. I, 2, plate 



xxiv, fig. 1. Maack, Palaeontogr., XVIII, 1869, p. 246. 

 Emys oweni, Leidy, Proc. Acad. Nat. Sci. Phila., v, 1851, p. 227. 

 Emys culbertsonii, Leidy, Proc. Acad. Nat. Sci. Phila., VI, 1852, p. 24. 

 Testudo hemispherica, Leidy, Proc. Acad. Nat. Sci. Phila. 1852, VI, p. 59; Owens' Rept. on Geol. Surv. 



Wis., Iowa, and Minn., 1852, p. 570, plate xiiB, figs. 1, 2; Ancient Fauna Neb. 1854, pp. 105, 115, 



plate xx, figs. I, 2, plate xxiv, fig. 2. Winckler, Arch. Mus. Teyler, 11, 1869, p. 146, plates 



xxxi-xxxm. Maack, Palaeontogr., xvm, i86q, p. 245. 

 Testudo nebrascensis, Leidy, Proc. Acad. Nat. Sci. Phila., vi, 1852, p. 59; Owen's Rept. on Geol. Surv. 



W r , l"u .1, .itul Minn., 1852, p. 567, plate xiiA, figs. I, 2; Ancient Fauna Neb., pp. 102, 1 15, plate 



\ix, hgs. 1 -3; Jour. Acad. Nat. Sci. Phila., (2), vii, 1869, p. 26 (Testudo, 01 Stylemys neb.); Contrib. 



Ext. fauna West. Terrs., 1873, p. 339, plate xix, figs. 7, 9, 10 Maack, Pakeontogr., xvm, 1869, 



p. 245. Marsh, Amer. Jour. Sci., (2), L, 1870, p. 292. Zittel, K. A., Handbuch Palaeont., Ill, 



iNXij, p. 540, fig. 501. 



Testudo oweni, Leidy, Proc. Acad. Nat. Sci. Phila., VI, 1S52, p. 59; Owen's Rept. on Geol. Surv. 

 Wis., Iowa, and Minn., 1852, p. 568, plate xiiA, figs. 3, 4; Ancient Fauna Neb., 1854, pp. 106, 115, 

 plate \m, tigs. 1, 1, plate xxiv, fig. 4. Maack, Pakeontogr., xvm, 1869, p. 245. 



Testudo culbertsonii, Leidy, Proc. Acad. Nat. Sci. Phila., vi, 1852^.59; Owen's Rept. on Geol. Surv. 

 Wis., Iowa, and Minn., 1852, pp. 569, plate xii, figs. 1, 2; Ancient Fauna Neb., 1854, pp. 108, 115, 

 plate xxii, tigs., 1, 2, plate xxiv, fig. 2. Maack, Palaeontogr., xvm, 1869, p. 246. Haberlandt, 

 Jahrb. k. k. Reichsanst., xxvi, 1876, p. 242. 



Emys nebrascensis, Leidy, 6th Ann. Rept. Smithson. Inst., 1851 (1852), p. 65. 



Emys lu. LEIDY, 6th Ann. Rept. Smithson. Inst., 1851 (1852), p. 65 



Stylemys culbertsonii, Core, Trans. Amer. Philos. Soc, xiv, 1869, p. 124. 



