134 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 75 



DESCRIPTION OF PLATE 17 



PAGE 



Burnetia urania (Walcott) 77 



Figs. 1,2. (Natural size.) Dorsal and side views of the type cra- 

 nid urn. U. S. Nat. Mus., Cat. No. 23861a. 

 3. (Natural size.) Associated free cheek. U. S. Nat. Mus., Cat. 

 No. 23861b. 



Matrix, granular limestone. 



Upper Cambrian, Cap Mountain formation. (Loc. 68) : Pack- 

 saddle Mountain, Llano County, Texas. 



Bynwima eumus (Walcott) • • 7^ 



Fig. 4. (Natural size.) Dorsal view of a typical cranidium. U. S. 

 Nat. Mus., Cat. No. 70255. 

 5,6. (Natural size.) Dorsal view and side outline of an exfoli- 

 ated cranidium, U. S. Nat. Mus., Cat. No. 70256. 



Matrix, limestone. 



Upper Cambrian, Lyell formation. (Locs. 66m, 64b) : Sawback 

 Range northwest of Lake Louise, Alberta, Canada. 



Ucebia ara Walcott 118 



Fig. 7. (X2.) Dorsal view of type cranidium. U. S. Nat. Mus., Cat. 

 No. 70257. 

 8. (X2.) A second cranidium. U. S. Nat. Mus., Cat. No. 70258. 



Matrix, limestone. 



Upper Cambrian, Warrior limestone. (Loc. 107k) : Center 

 County, Pennsylvania. 



Elvinia roeyneri ( Shumard) 88 



Figs. 9, ID. (Natural size.) Dorsal and side views of the cranidium 

 chosen as representing Shumard's conception of this species. 

 U. S. Nat. Mus., Cat. No. 70259. 



11. (Natural size.) Associated free cheek. U. S. Nat. Mus., Cat. 



No. 70260. 



12, 13. (Natural size.) Dorsal and side views of associated pygid- 



ium assigned to this species. U. S. Nat. Mus., Cat. No. 70261. 



Matrix, granular limestone. 



Upper Cambrian, Cap Mountain formation. (Loc. 68) : Pack- 

 saddle Mountain; (Loc. 70) : Morgans Creek, Texas. 



Vistoia prisca Walcott 122 



Fig. 14. (X 2.) Dorsal view of an entire dorsal shield slightly com- 

 pressed laterally. U. S. Nat. Mus., Cat. No. 70262. 



Matrix, fine-grained siliceous shale. 



Middle Cambrian, Chetang formation. (Loc. 62f) : Southwest 

 base of Robson Peak, British Columbia, Canada. 



Taenicephalus shumardi (Hall) Ulrich and Resser 117 



Fig. 15. (X2.) Cranidium with outlines restored. U. S. Nat. Mus., 

 Cat. No. 70263. 



16. (X 2.) Free cheek. U. S. Nat. Mus., Cat. No. 70264. 



17. (X2.) Pygidium assigned to tlie species. U. S. Nat. Mus., 



Cat. No. 70265. 



Matrix, sandstone. ' 



Upper Cambrian, Franconia formation. (Loc. 83) : Trempealeau, 

 Wisconsin. 



