NO. 7 CAMBRO-ORDOVICIAN FOSSILS 237 



DESCRIPTION OF PLATE 35 (Continued) 



PAGE 



Ceratopyge canadensis Walcott 233 



Fig. 13. (X3) A somewhat imperfect hypostoma associated with 

 this species. U. S. National Museum, Catalogue No. 58353. 



14. (Natural size.) Free cheek. U. S. National Museum, Cata- 



logue No. 58354- 



15. (X 2.) Cranidium flattened in the shale, but preserving many 



of its characters. U. S. National Museum, Catalogue No. 

 58355. 



16. (Natural size.) An imperfect pygidium flattened in the shale. 



U. S. National Museum, Catalogue No. 58356. 



17. (Natural size.) Imperfect pygidium, showing a lateral spine 



on each side. U. S. National Museum, Catalogue No. 



58357. 



18. (X2.) A small pygidium, showing the anterior segment ex- 



tended into a spine. U. S. National Museum, Catalogue 

 No. 58358. 



19. (Natural size.) Matrix of a pygidium with its anterior seg- 



ment. U. S. National Museum, Catalogue No. 58359. 



20. (Natural size.) An entire exfoliated dorsal shield very much 



shortened by compression. U. S. National Museum, Cata- 

 logue No. 58360. 



21. (Natural size.) An imperfect dorsal shield, somewhat dis- 



torted, but still preserving what was probably its natural 

 form and outline. U. S. National Museum, Catalogue No. 

 58361. 



22. (Natural size.) An imperfect dorsal shield elongated by 



lateral compression. U. S. National Museum, Catalogue 

 No. 58362. 



