434 G. R. Wieland— Upper Cretaceous Turtles. 



detailed description of the form of the individual elements 

 unnecessary. These figures show in particular the enormous 

 thickness of the elements of the plastron, which is especially 

 heavy near to the hypo-xiphiplastral suture. There was, how- 

 ever, no trace of fusion with the pubes. The hornshields 

 are for the greater part indicated by narrow sulci not accen- 

 tuated in the nuchal region as in Adocus, with the inner 



Figure 5. — Agomphus tardus. Plastral view drawn from the type. P, 

 pectoral, V, ventral, F, femoral, and A, anal hornshields ; en, entoplastron. 

 Other letters and numbers as in figures 2 and 3. 



borders of the marginalia, as is especially to be noted, not 

 traversing the pleuralia as in that genus, but continuing below 

 the pleuro-marginal sutures all round the carapace from the 

 nuchal to the pygal region. 



Specific Relationships. — The forms with which Agomphus 

 tardus is to be compared are (1) A. (Emys) firmus (Leidy), 



