42 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 53 



DESCRIPTION OF PLATE i 



Page 



Bathynriscus oniatiis, new species 39 



Fig. I. A broken specimen, showing character of cephalon and thorax. 

 U. S. National Museum, Catalogue No. 53420. 



2. A small nearly entire dorsal shield, with the exception of the 



free cheeks. U. S. National Museum, Catalogue No. 53421. 



3. Two segments of the thorax enlarged to show the details of the 



axial and pleural lobes. U. S. National Museum, Catalogue 

 No. 53423. 



The specimens represented by figures 1-3 are from the Mid- 

 dle Cambrian Ogygopsis shale of the Stephen formation, 

 2,400 feet (731.5 m.) above the Lower Cambrian, on the north- 

 west slope of Mt. Stephen, near Field, British Columbia. 



Albertella bosivorthi, new genus and new species 22 



Fig. 4. Cephalon, showing character of the palpebral lobes. Compare 

 this with the cephalon of Albertella hclena on pi. 2, figs, i, 4, 

 and 5. U. S. National Museum, Catalogue No. 53413. 



5. A specimen showing the character of the thorax and pygidium. 



U. S. National Museum, Catalogue No. 53416. 



6. Pygidium, which compare with pygidium of A. hclena pi. 2, fig. 



2. U. S. National Museum, Catalogue No. 53415. 



7. Inner side of a very small pj^gidium. U. S. National Museum, 



Catalogvie No. 53406. 



The specimens represented by figures 4-7 are from a drift 

 block of Lower Cambrian shales found on the slopes of Mt. 

 Bosworth, just north of the Canadian Pacific Railway, one 

 mile (0.62 km.) east of Hector, British Columbia. 



Buxlingia h'ectori, new genus and new species 15 



Fig. 8. A nearly entire specimen greatly enlarged. U. S. National 

 Museum, Catalogue No. 53418. 



The specimen represented by figure 8 is from the Middle 

 Cambrian Ogygopsis shale of the Stephen formation, 2,400 

 feet (731.5 m.) above the Lower Cambrian, on the northwest 

 slope of Mt. Stephen, near Field, British Columbia. 



Oryctocara geikici. new genus and new species 23 



Fig. 9. A nearly entire dorsal shield with the exception of the free 

 cheeks. U. S. National ]\Iu?eum, Catalogue No. 53426. 

 10. Greatly enlarged matrix of a small pygidium. U. S. National 

 Museum, Catalogue No. 53427. 



The specimens represented by figures 9-10 are from the 

 Spence shale of the Ute formation, near the base of the Mid- 

 dle Cambrian, in a ravine running up into Danish Flat from 

 Mill Canyon, about 15 miles (9.37 km.) west of Montpelier, 

 and 5 miles (3.12 km.) west-southwest of Liberty, Bear Lake 

 Countv, Idaho. 



