GILMORE: the fossil turtles of the UINTA FORMATION 121 



It is estimated that the entire shell had a length of about 495 mm., and a height 

 at the center of about 170 mm. The plastron had a length of about 420 mm. The 

 anterior lobe at the base is 156 mm. wide. The bridge is 180 mm. wide. 



The posterior lobe has a width at the base of 152 mm., and a length of 128 mm. 

 The lateral borders of the lobe are nearly straight and converge nearly the entire 

 length of the lobe, there being a slight constriction at the anal-femoral sulcus. The 

 posterior end of this lobe is broadly but evenly rounded and without median emar- 

 gination. At the anal-femoral sulcus the transverse measurement is 107 mm. 



The mesoplastrals are solidly coossified with the contiguous bones and their 

 boundaries can only be determined by the ridges which cut them at right angles. 

 At the midline these bones have a width of 33 mm., at their outer ends they expand 

 to 55 mm. in width. 



As in Ba'ena sima Hay, the median sulcus runs a very tortuous course, as is well 

 shown in Fig. 8. The pectorals meet on the median line for a distance of 77 mm.; 

 the abdominals for 70 mm.; the femorals for 68 mm.; the anals for 85 mm. The 

 anal-femoral sulcus runs in from the border a short distance, then turns abruptly 

 forward, then again turns at right angles toward the median line to meet the scute 

 of the opposite side. In the shape of the anal scutes it resembles Ba'ena arenosa 

 and more especially B. clara. 



Owing to the damaged condition of the bridges the number of inframarginal 

 scutes cannot be determined. 



Family DERMATEMYDID^ Gray. 



The family Dermatemydidse is represented now for the first time in the Uinta 

 formation by the single genus and species, Anosteira ornata Leidy. This is the 

 latest recorded occurrence of this genus for North America, although in England 

 it is known to range upward into the Lower Oligocene. 



Genus Anosteira Leidy. 



6. Anosteira ornata Leidy. 



Anosteira ornata Leidy, Proc. Acad. Nat. Sci. Phila., 1871, p. 102; Ann. Report 

 U. S. Geol. Surv. Montana, etc., 1871 (1872), p. 370; Contrib. Ext. Fauna 

 West. Terrs., 1873, pp. 174, 341, pi. XVI, figs. 1-6.— Hay, Bibliog. and Cat. 

 Foss. Vert. N. A., 1902, p. 447; Bull. Amer. Mus. Nat. Hist., XXII, 1906, 

 p. 157, figs. 2, 3; Fossil Turtles of North America, 1908, pp. 279-281, PI. XLIII, 

 figs. 1, 2; text-figs. 352-354. 



