PE0E. H. Cf. SEELEY ON PELOBATOCHELYS BLAKH ETC. 237 



extend transversely for about an inch on each side. The costal plates 

 thicken considerably but gradually near their union with the neural 

 plates. On the underside the ribs are very slightly elevated, though 

 broad and clearly denned. 



"With this evidence Mr. Blake's materials terminate; but the British- 

 Museum specimen shows that the seventh and eighth neural plates are 

 crossed by the border of th e fourth vertebral scute, which is 4 inches long. 

 The anterior border rises considerably above the posterior border. 



The pygal (?) plate is indented behind concavely, and impressed 

 by a broad Y-shaped scutal line, which divides the pygal scute. 



This genus approaches closely to the Palceomedusa testa of the 

 Lithographic Slate. 



EXPLANATION OF PLATE XIII. 



Fig. 1. Carapace of Pelobatochelys Blakii, from above, restored outline, |- natural 

 size, showing the boundaries of the scutes in outline and the portions 

 of the plates in the collections of Mr. Blake and the British Museum 

 shaded. 



a. Nuchal plate. 



b. From the British- Museum specimen. 



c. Pygal plate, in the British Museum. 



d. Marginal plate, in the British Museum. 

 V. 1-V. 5. Vertebral scutes. 



Fig. 2. Side view of the same, showing the outlines of the scutes, £ natural size. 



