24 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 97 



depressed in center, giving rise to the appearance of the anterior, and 

 dorsal furrows crossing each other in the center. 



Name. — crrai'po? = cross ; oA-kos = furrow. 



Genotype. — .S". typicalis, new species. 



STAUROHOLCUS TYPICALIS, n. sp. 



Plate 5, figs. 7, 8 



The illustrations and generic description portray the specific char- 

 acters. 



Locality 55c. 



Holotype cnul parafypes. — U.S.N.M. no. 96528. 



REFERENCES 

 Deiss, Charles. 



1938. Cambrian formations and sections in part of Cordilleran trough. 



Bull. Geol. Soc. Amer., vol. 49, pp. 1067-1168. 



1939. Cambrian stratigraphy and trilobites of northwestern Montana. Geol. 



Soc. Amer., Spec. Paper 18. 

 Resser, C. E. 



1938. Middle Cambrian fossils from Pend Oreille Lake, Idaho. Smithsonian 

 Misc. Coll., vol. 97, no. 3. 

 Walcott, C. D. 



1908a. Nomenclature of some Cambrian Cordilleran formations. Smith- 

 sonian Misc. Coll., vol. 53, no. i, April. 

 1908b. Cambrian sections of the Cordilleran area, Smithsonian Misc. Coll., 

 vol. S3, no. 5, December. 



EXPLANATION OF PLATES 



All figures are natural size unless otherwise designated. Species without 

 locality references are all from locality 55c. 



Plate i 



PAGE 



LhignJcUa cucharis, new species 5 



Fig. I. Ventral valve (X3)- 



Figs. 2, 3. Two dorsal valves (X3.5). 

 Acrotreta levata, new species 6 



Fig. 4. Narrow false pedicle groove (X 6). 



Fig. 5. Interior of ventral valve (X6). 



Fig. 6. Interior of dorsal valve (X3). 

 Acrotreta definita Walcott 5 



Fig. 7. Exterior ventral valve (X4)- 



Figs. 8, 9. Exterior and interior of dorsal valves ( X 4 > • 



Fig. id. Interior ventral valve (X4). 

 Micromitra lepida, new species 4 



Fig. II. Somewhat crushed ventral valve (X1.5). 



Figs. 12, 13. Exterior and interior of dorsal valve (X 1.5). 



