108 



G. R. Wieland — On Marine Turtles. 



the articular digitations and grooves corresponding to those of 

 the next member of the marginal series, namely, the third, 

 which is also complete and is followed by a fourth in equally 

 good preservation. I am thus explicit, because it is important 

 to note that all the anterior border of the carapace is indicated 

 with certainty, and shows the presence of a peculiar upturning 



Fig. 3. 



Figure 3. — Protostega Copei. Plastron of the type x 1/7 nearly. The 

 hypo-xiphilastrae are especially well conserved, and the left hyoplastron in 

 fair condition. The right hyoplastron and portions of the T-shaped epiplas- 

 tron are not present ; and as indicated in the figure, the ends of most of 

 the digitations of all the elements are missing. Nevertheless the plastral 

 form is quite accurately indicated in its entirety by the original specimen 

 as here outlined. 



of the portion of the carapacial edge formed by the junction of 

 the third and fourth marginals. Evidence is here furnished 

 that the strong anterior and much upturned prolongation of 

 the third marginal of Archelon was an articulating portion 



