em 



118 G. JR. Wieland — Upper Cretaceous Turtles, 



(4) Elements of the Plastron. 



Greatest length Greatest lateral 



on median line. width. 



Epiplastron 2"5 cm 6'5 cm 



Entoplastron 5-0 6'8 



Hyoplastron 6*0 14'0 



Hypoplastron 10*5 14*0 



Xiphiplastron . 11* 8* 



(5) Plastral Horn Shields. 



Greatest length Greatest lateral 

 on median line. width. 



Intergular ._ 2-5 3 



Gular (3- ) (4- ) 



Humeral 4- 8 



Pectoral 4* 11 



Ventral 9*0 11 



Femoral 8*5 9 



Anal 7*5 7 



(6) Thickness of various elements. 



Nuchal (at anterior median border) . 1-1 



" (at posterior end) *3 + 



lst Neural (at anterior end) _ *4 



1st " (at posterior end) __ 1*0 



5th " (anterior) _ _ 1-0 



5th " (posterior) 1*0 



7th " (average) -5 



1st Marginal (at the marginal-vertebral-costal horn shield 



intersection) _ 2-0 



llthMarginal 1*3 



II. Osteopygis Gibbi sp. nov. — (Plates V-VIII.) 



The genus Osteopygis was proposed by Cope in 1868* for 

 the reception of certain fossil turtles from the Upper Creta- 

 ceous Green sand Bed of New Jersey. In all some seven species 

 have been referred to this genus. But they are quite without 

 exception based on fragmentary material, for the greater part 

 insufficiently illustrated and described. It is hence with the 

 utmost difficulty, if at all, that one may adjudge the value of 

 the several species without having at hand all of tfie types, which 

 urgently require redescription and adequate illustration. This 

 being the fact, the restoration for the iirst time of the complete 

 shell of Osteopygis must be of immediate service and interest. 

 The possibility of such a restoration is afforded by Yale Speci- 

 men No. 783. 



* Proceedings of the Academy of Natural Sciences, Philadelphia, 1868, p. 

 147. 



