110 



G. B. Wieland — On Marine Turtles. 



ciently exhibit not merely their characters, but their chief 

 dimensions. Certain measurements, however, are appended, as 

 follows : 



Length of cranium from snout to condyle (accurate) __ 24'0 cm 



Greatest width of cranium across the condyles (close).. 20*0 



Length of lower jaw (on median line) 15*0 



Length of carapace (estimated) 80- + 



Greatest length of plastron 63*5 ± 



Greatest width of plastron . 66*0 



Greatest thickness of plastral elements measured through 

 their centers of ossification : 



Entoplastron __ 15 ,mm 



Hyoplastron 23* 



Hypoplastron _. 20* 



Xiphiplastron 13* 



Fig. 5. 



Figure 5. — Protostega (Archelon) Marshii. Eight third marginal x|. Dorsal 

 view to the left, and ventral view showing large pit for the second rib to the 

 right. [Dactylations should be represented as distinctly acuminate, but not 

 much longer. J Observe, that as proven in Protostega Copei, articulation with 

 the second marginal was formed "by the long upward and forward projection, 

 resulting in abrupt change in direction of the marginal line at the humeral 

 notch, as revealed further by the figures of the entire skeleton. 



Protostega (Archelon) Marshii Wieland 11 (Figure 5). 



In this Journal for April, 1900, 1 gave a brief description of 

 a new species of Archelon, which was based on the portion of 

 a skeleton collected by me in 1898, on the left bank of the 

 Cheyenne River. Until further material is found, as will with 

 certainty transpire, the fragmentary condition of the present 

 remains will scarcely justify much work upon them by a pre- 



