6o 



FOSSIL TURTLES OF NORTH AMERICA. 



the rim of the orbit. Triturating surface of the maxilla furnisht with a prominent longitudinal 

 ridge. Choanae opening on a line joining the fronts of the orbits. 



KEY TO SPECIES OF BAENA. 

 A 1 . Judith River species. 



1. Length of anterior lobe 0.60, its width 0.82, of width of bridge; width of hinder lobe 



0.94 of width of bridge; entoplastron longer than broad callosa 



2. Plastron known only from part of anterior lobe; the entoplastron broader than long . . antiqua 

 A 2 . Laramie species. 



1. Length of anterior lobe 0.92, its width l.oo, of width of bridge; width of hinder lobe 



1 . 04 of width of bridge hatchen 



2. Length of anterior lobe 0.58, its length 0.79, of width of bridge; width hinder lobe 0.75 



of width of bridge marshi 



A . Torrejon species escavada 



A*. Bridger species. 



1. Shell broad behind and deeply scallopt; strongly sculptured on back arenosa 



2. Not so strongly sculptured; a broad groove along the back riparia 



3. Shell oval, thin; the sculpture broken up into wrinkles; no median groove sima 



4. Shell oval; rounded behind; nearly smooth clara 



A^. Unita species emilite 



Baena callosa Hay. 

 Plate 8, fig. i; teit-figs. 35, 36. 

 Baena callosa, HAY, Ann. Carnegie Museum, III, 1904, p. 178, plate ix, text-figs. I, 2. 



This species is based on an incomplete shell which belongs to the Carnegie Museum, in 

 Pittsburg, Pennsylvania. The number is 330. It was collected in the year 1903, by Mr. J. B. 

 Hatcher, in the Judith River beds of Willow Creek, Gallatin County, Montana. 



The posterior fourth of the carapace is missing; and of the anterior three-fourths, many of 

 the peripherals and portions of the costals are wanting (text-fig. 35). The entire length of the 



Figs. 35 and 36. Baena callosa. Type. X.?. 



35. Carapace, c. s. i, c. s. ^, etc., costal scutes; v. s. i , v. s. 2, etc., vertebral scutes. 



36. Plastron, ab, abdominal scute; an, anal scute; ent, entoplastron; epi, epiplastron; fern, femoral scute; g y gular 



scute; /rum, humeral scute; hyo, hyoplastron; hypo, hypoplastron; ig, intergular scute; mes, mesoplastron; 

 fee, pectoral scute; xifh, liphiplastron. 



