392 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 53 



DESCRIPTION OF PLATE 29 



PAGE 

 Holmia roivei, new species 292 



Figs, i and 2. Two flattened specimens of the cephalon showing strong 

 marginal rim, genal spines, and occipital spine. Natural size. 

 U. S. National Museum, Catalogue Nos. 56801a and s68oib, 

 respectively. 



3. A nearly entire specimen of the dorsal shield with seventeen 



thoracic segments, the cephalon, and a portion of the pygidium. 

 Natural size. U. S. National Museum, Catalogue No. 56801^. 



4. A portion of the thorax preserving seventeen segments and 



showing the form of the termination of the segments. X 2. 

 U. S. National Museum, Catalogue No. 56801^. 



5. A portion of the cephalon and thorax. Note the very long 



genal spine. Natural size. U. S. National Museum, Cata- 

 logue No. 56801^. 



6. A nearly entire cephalon. X 2. U. S. National Museum, Cata- 



logue No. 56801/". 



7. Enlargement of a portion of the outer surface of the cheek of 



the cephalon showing scattered tubercles. X 9- U. S. Na- 

 tional Museum, Catalogue No. 56801^. 



8. Enlargement of a portion of the surface of the cheek on which 



the reticulated net work formed by narrow ridges is very 



clearly shown. X 12. U. S. National Museum, Catalogue 

 No. 56801/1. 



9. Fragment of a minute cephalon showing a young stage of 



growth. X 12. Compare with young of Wanneria halli (pi. 31, 

 figs. 5 and 8), Elliptocephala asaphoides (pi. 25, figs. 9 and 

 10), and Pcsdeumias transitans (pi. 25, fig. 21). U. S. Na- 

 tional Museum, Catalogue No. 56801/. 



10. A small specimen of the cephalon with a portion of the thorax. 



Natural size. U. S. National Museum, Catalogue No. 56801;. 



11. The only entire pygidium found in the collection. X 2. U. S. 



National Museum, Catalogue No. 56801/^. 



All the specimens represented on this plate are from locality 

 (if), 10 miles south of Silver Peak and three miles northeast 

 of Barrel Spring, Nevada. 



