G. R. Wieland — Upper Cretaceous Turtles. 431 



shell of another genus of a well represented Upper Cretaceous 

 to Tertiary family, the Adocidse, and as being relatively the 

 heaviest and most massive turtle shell yet discovered. Although 

 originally a perfect fossil with suturally united carapace and 

 plastron, only thirteen complete and five incomplete elements of 

 the carapace, together w T ith the hyo- and hypopiastron, have 

 escaped the accidents of discovery and collection. Of the imper- 

 fect parts but four are diagnostic as to form, whence the recov- 

 ered elements that are wholly determinative virtually number 



Figure 1. — Agomphus tardus Wieland (sp. nov.). Carapace and plastron 

 of type specimen* with the missing portions restored in the estimated 

 natural size and position. Actual length of carapace 33 cm . Elements present 

 indicated in the succeeding figures 2-5. 



but nineteen, or exactly one-third of the original fifty-seven 

 elements of which the carapace and plastron was composed. 

 These recovered elements of grayish to dark, marl green color, 

 are however perfectly fossilized, uncrushed, disarticulated, and 

 without crumbling or breaking of the sutural faces. Moreover 

 they are by a rare and noteworthy chance so distributed as to 

 clearly outline the missing elements and make possible a res- 

 toration by the Museum preparateur, Mr. Gibb, and the writer, 

 which it is confidently believed by both will be found essen- 



* Elements present : nuchal (incomplete), 2d and 5th neurals, left 1st and 

 2d pleurals, right 4th and 5th pleurals (incomplete), right 6th and 7th 

 pleurals, left 2d marginal, left 5th and 6th marginals (incomplete), left 10th 

 and 11th marginals, right 8th-llth marginals, the left hyo- and the right 

 hypopiastron. 



