426 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 64 



DESCRIPTION OF PLATE 52 



PAGE 



Dolichometopus boccar Walcott 363 



Fig. I. (Natural size.) Matrix of a dorsal shield, flattened in very fine 

 arenaceous or siliceous shale. U. S. National Museum, 

 Catalogue No. 62702. 

 From locality 14s, Middle Cambrian : Stephen formation ; Mount 

 Stephen, British Columbia, Canada. 



la. (Natural size.) Partially restored figure of a dorsal shield. 



U. S. National Museum, Catalogue No. 62703. 

 lb. (Natural size.) Cranidium embedded in compact limestone. 



U. S. National Museum, Catalogue No. 62704. 

 ic. (Natural size.) Cranidium flattened in shaly limestone. U. S. 



National Museum, Catalogue No. 62705. 

 id. (X4.) Hypostoma. U. S. National Museum, Catalogue No. 



62706. 

 le. (Natural size.) Pygidium and five thoracic segments flattened 



in shaly limestone. U. S. National Museum, Catalogue No. 



62707. 

 i/, i/'- (X 2.) Dorsal and side views of a pygidium preserved in 



compact limestone. U. S. National Museum, Catalogue No. 



62708. 



The specimens represented by figs. la-f are from limestone at 

 locality sjg. Middle Cambrian: Stephen formation; Mount Bos- 

 worth, British Columbia, Canada. 



Dolichometopus bioii Walcott 363 



Fig. 2. (X 1-5-) Cranidium. U. S. National Museum, Catalogue No. 

 62709. 

 2a. (Natural size.) Matrix of a pygidium. U. S. National Museum, 



Catalogue No. 62710. 

 2b. (Natural size.) A large pygidium. U. S. National Museum, 



Catalogue No. 62711. 

 2c. (X 3-) A small pygidium enlarged. U. S. National Museum, 

 Catalogue No. 62712. 



The specimens represented by figs. 2, 2a-c occur in a fine argil- 

 laceous shale at locality 55c, Middle Cambrian: Spence shale; 15 

 miles (24 km.) west of Montpelier, Idaho. 



