268 



FOSSIL TURTLES OF NORTH AMERICA. 



appeals to be missing. The figure presents the inner, or visceral, surface. This bone is 4 mm. 

 thick at its anterior border, but toward the other border it thickens greatly, so that a little 

 beyond the middle of the width the thickness is 10 mm. From the line of its greatest thickness 

 the bone is beveled off on the inner side to its hinder border, and against this beveled surface 

 the sixth costal has articulated. A strongly developt buttress from the plastron ascended 

 against the inner surfaces of these two costals at their junction. The scar for this buttress on 

 the fifth costal here figured is 20 mm. long. The plastron was therefore articulated with the 



33 1 - 33- 329- 



I ics. 329-331. Kalhstira costdata. Costals of the type. Xl. 



329. Proximal end of costal, second or fourth. 



330. Proximal end of costal, showing a carina. 



331. Distal end of costal, probably the fifth, showing scar 



for inguinal buttress of plastron. 



carapace in a very different way from that seen in other dermatemyds; and a distinct genus 

 is indicated. 



Portions of 3 neurals are at hand, those represented by Cope's figs. 18, 22, and 25. The 

 first-mentioned (fig. 332) has a width of 22 mm., probably belonged well forward, and was 

 possibly the second. The median carina is barely perceptible. No sulcus crosses the portion 

 present. That part of a neural from which Cope's fig. 25 was drawn (fig. 332a) is narrow and 

 devoid of a carina. It is crost near the fracture bv a narrow and shallow sulcus. It appears quite 

 probable that this is the posterior end of the first neural. At its lateral border it is 5 mm. thick. 



The neural represented by Cope's fig. 22 (fig. m) apparently belonged to the rear of the 

 carapace, and resembles closely the sixth of Staurotypus salvinii. Its length is 18 mm.; 



332- 

 Figs. 



532a. 



332-534. Kallistira costilata. Neurals and a peripheral of type. 



532, l\za. Portions of two neurals of the type. 332 is Cope's fig. 18; 



332*2 Cope's fig. 25. 

 133. A hinder neural, showing carina. Cope's fig. 22. 

 , ,4. A hinder peripheral with a section (a) across it. 



:h the 



greatest breadth about 20 mm.; thickness at the lateral border 4.5 mm., throug 

 9.5 mm. The carina is sharply defined and wider in front than behind. 



A portion of a hinder peripheral is present, being the original ot Cope's figs. 29 and 29(2, 

 and constituting, according to Cope, a portion of the same individual as those furnishing his 

 figs. 27 and 30. Cope's figure is inverted. This (fig. 334) bone has a height ot 27 mm. in a 

 direct line, and a maximum thickness of 7 mm. Its width can not be determined, as the bone 

 has been broken near the descending sulcus. This sulcus, in contradistinction to those ot the 

 costals and neurals, is broad and deeply and irregularly imprest. Along the upper border ot 

 the bone runs what appeals to be the longitudinal, or costo-marginal, sulcus. On the under 



