116 G. R. Wieland — Upper Cretaceous Turtles. 



As pointed out by Marsh and later by Baur,* the nearest 

 living relative of Adocus (the type genus of the Adocidae of 



Figure 2. — a. Adocus beatus (type), left 1st marginal, x £. . After Leidy. 

 b. Adocus punctatiis, Marsh (type), left 1st marginal, x £. 



Copef) is Dermatemys of Yucatan, which with the genera 

 Staurotypus and Claudius of Mexico and Central America, 

 constitute the Dermatemydidm. 



The arrangement of the neuralia of Dermatemys is much 

 the same as in Adocus, but there are only 46 plates in the 

 carapace as figured by Boulanger (Brit. Mus. Cat.), the 7th 

 pleural being large and representing the 7th and 8th of 

 Adocus. Also, not only the first, but all the succeeding costals 

 overlap the marginals. Dermatemys likewise differs markedly 

 in the presence of a costiform process of the nuchal. 



Four inframarginals are present, but there are no separate 

 paired gulars as in Adocus. Unlike the latter, the plastron is 

 notched posteriorly. 



Measurements of Adocus punctatiis Marsh (type). 

 Skeletal parts uncrushed. 



(1) The Carapace. 



Length on straight line 54. om 



Length over curvature ._ _ 60. 



Greatest width (across 5th neural) 37. 



Distance over curvature across 5th neural 51. 



Projection beyond front end of plastron 6.8 



Projection be} T ond hinder end of plastron 12.2 



* Proceedings of the Academy of Natural Sciences, Philadelphia, 1891, 

 vol. xliii, p. 428-430. 

 f Proc. Amer. Phil. Soc, Philadelphia, 1870, xi, p. 515. 



