NO. 5 CAMBRIAN TRILOBITES 437 



PAGE 



Corynexochus (Boniiia) ficldensis (Walcott) 327 



Figs. 4, 4'. (X 3-) Dorsal and side views of the type cranidium. U. S. 

 National Museum, Catalogue No. 62751. 

 40,40'. (X3-) Dorsal and side views of a pygidium associated with 

 the cranidium represented by fig. 5. U. S. National Museum, 

 Catalogue No. 62752. 

 4b. (X4-) Associated hypostoma. U. S. National Museum, Cata- 

 logue No. 62753. 



The specimens represented by figs. 4, 40-^7 are from the limestone 

 of locality 35 I, Lower Cambrian : Ptarmigan Pass, Alberta, Canada. 



