526 



FOSSIL TURTLES OF NORTH AMERICA. 



given in the table below. Of these neurals, the anterior was probably about as wide in 

 front as behind. The next three have, as usual in the family, the narrower end directed for- 

 ward. The fifth has the anterior end only slightly narrower than the hinder end. The sixth 

 has the broader end in front. The seventh is heptagonal. 



At the free border the costals are beveled off on the upper side. 



681. 



682. 



FIGS. 681-683. Amyda? exquisita. Type. 



681. Carapace. X J. Parts ruled with parallel lines are missing. 

 682. Antero-posterior median section of nuchal. Xi. 683. Plastron. XJ- 



On most portions of the carapace the sculpture, consisting of pits, is coarse. The bottoms 

 of the pits slope up to the summits of the rounded walls. The average diameter is about 5 mm. 



On the hinder border of the nuchal the pits are smaller, about 5 

 in a line 20 mm. long. Those along the free border, too, have 

 this size. On the proximal two-thirds or more of the costals 

 there are usually 4 pits in a 20 mm. line. On the hinder third 

 of the carapace they are still larger, 3 and sometimes only 2.5 

 in the line mentioned. Those on the anterior 4 or 5 neurals are 

 very shallow. 



The plastron (fig. 683) is remarkable for the narrowness of 

 the bridges and the depth of the notch between the outer proc- 

 ess of the hyoplastron and that of the hypoplastron. The 

 width of the bridge is only 47 mm.; in the paratype, No. 5943, an individual apparently as 

 large as the type, the width is only 39 mm. The size of the fontanel inclosed between the 

 outstanding processes of the plastral bones mentioned may be judged from the accompanying 

 figure. There were also extensive fontanels along the midline. 



