4 PROCEEDINGS OF THE NATIONAL MUSEUM voi i6 



EXPLANATION OF PLATES 



Plate 1 



Leift: Ventral view of the carapace described above, X %. 

 Right: Dorsal view, X Ys. A foot rule is shown at the side. 



Plate 2 



Upper: A fragment forming the distal end of the fifth costal of the right 



side to show the sculpturing, X %. 

 Center: One of the type specimens. Distal portion of a costal plate, X 1. 



Museum Wagner Free Institute of Science, Philadelphia. 

 Lower: Type specimen. Proximal portion of a costal plate, X 1. Wagner 



Free Institute of Science, Philadelphia. 



U. S. GOVERNMENT PRINTING OFFICE: I92» 



