20. PLESTIODON 589 



skiltonianus, but this has not yet been shown to be the case. 

 The two known specimens agreed perfectly in their charac- 

 ters. It is true that specimens of P. skiltonianus sometimes 

 have pinkish tails, but I have seen none with the interparietal 

 plate reduced as in P. lagunensis. I, therefore, for the 

 present, continue to recognize this species as distinct, 

 especially since the record of P. skiltonianus from the Cape 

 Region of Lower California seems to be founded on error. 



132. Plestiodon obsoletus Baird & Girard 



SONORAN SkINK 



Plate 57 



Plestiodon obsoletum Baird & Girard, Proc. Acad. Nat. Sci. Phlla., 

 Vol. 6, 1852, p. 129 (type locality, Valley of the Rio San Pedro, 

 tributary of the Rio Grande del Norte, Texas); Hallowell, 

 Sitgreaves' Exped. Zuni and Colorado Riv., 1853, p. in. 



Plestiodon obsoletus Baird, U. S. Mex. Bound. Surv., Vol. 11, Rept., 

 1859, p. 12, pi. 25, figs. 9-16; Baird, Pac. R. R. Surv., Vol. X, 

 1859, p. 39; Stejneger & Barbour, Check List N. Amer. Amph. 

 Rept., 1917, p. 70. 



Plistodon obsoletus Cope, Proc. Acad. Nat. Sci. Phila., 1866, p. 304. 



Eumeces obsoletus Cope, Bull. U. S. Nat. Mus., No. i, 1875, p. 45; Yar- 

 row, Surv. W. looth Merid., Vol. V, 1875, p. 556; Coues, Surv. 

 W. looth Merid., Vol. V, 1875, p. 604; Cope, Bull. U. S. Nat. 

 Mus., No. 17, 1880, p. 39; Yarrow, Bull. U. S. Nat. Mus., No. 

 24, 1883, p. 40; BocouRT, Miss. Sci. Mex., Rept., 1887, p. 443, 

 pis. XXII A, fig. 4, XXII D fig 4; Boulenger, Cat. Lizards 

 Brit. Mus., Vol. Ill, 1887, p. 374; Cope, Bull. U. S. Nat. Mus., 

 No. 32, 1887, p. 46; Van Denburgh, Proc. Cal. Acad. Sci., Ser. 

 2, Vol. 6, 1896, p. 346; Cope, Report U. S. Nat. Mus. for 1898, 

 1900, p. 646, fig. 128; Brown, Proc. Acad. Nat. Sci. Phila., 1903, 

 p. 548; Bailey, N. Amer. Fauna, No. 25, 1905, pp. 35, 45; Cragin, 

 Trans. Kansas Acad. Sci., Vol. VII, reprint 1906, p. 115; Stone, 

 Proc. Acad. Nat. Sci. Phila., 1911, p. 231; Ellis & Henderson, 

 Univ. Colorado Studies, Vol. X, No. 2, 1913, p. 79, pi. Ill, figs. 

 15, 16; VA>f Denburgh & Slevin, Proc. Cal. Acad. Sci., Ser. 4, 

 Vol. 3, 1913, p. 393; Strecker, Baylor Bulletin, Vol. XVIII, No. 

 4, 1915, p. 26. 



