EXPLANATION OF PLATE XVII 



Ceraurus milleranus Miller and Gurley, page 71. 

 Fig. 1. A complete cranidium. Mus. No. P 16853. X I. 

 Fig. 2. A pygidium with one spine missing. Mus. No. P 16925. X 1. 

 Fig. 3. The type specimen. No. 6062 University of Chicago. X I. 



Ceraurus elginensis sp. nov., page 73. 

 Fig. 4. The holotype. Mus. No. P 16630A. X I. 

 Fig. 5. A pygidium referred to this species. Mus. No. P 17030. X I. 



Eccoptochile? meekanus S. A. Miller, page 75. 



Figs. 6, 7. Two views of a coiled specimen in the collection of Mr. A. G. 

 Becker. X I. 



Fig. 8. An imperfect cranidium showing the form of the facial suture and the 

 posterior margin. Mus. No. P n 150. X 1. 



Fig. 9. Ventral view of a complete pygidium. Mus. No. P 11150. X 1. 



