PLATE XII —Continued. 
Page. 
DICELLOCEPHALUS BINAUIS "heme maar anette eee ase ee eee See ee 89 
Fig. 12. View of the central portions of the head. Natural size. 
12a. Associated pygidium, enlarged to two diameters. 
22. Portion of a thoracic segment on the same fragment of rock. 
AMPHION NEVADENSIS..o2.0..c-2)es¢c-00-eeeece---s Se Seno Sen one SS cee dG 6Os0 Se OAS SAO 94 
Fig. 13. View of the portions of the head preserved in the type specime. Natural size. 
14. Pygidium of unknown generic and specific relations, occurring in association wit 
Asaphus Caribouensis, enlarged to three diameters. 
ASAPHUS ? CURIOSUS ? ..-..- eine Satie a decmee oe seo teen eee eee = eee ane ee 98 
Fig. 15. Pygidium associated with Asaphus Caribouensis, enlarged to two diameters, 
SYMPHYSURUS? ‘GOMDKUSSI ...5.0 - stecece serine =e teste eee maroon ae nee ee 95 
Fig. 16. View of the glabella and portions of the fixed cheeks, enlarged to two diameters. 
CERAURUB frase cccae ee delete os bine se aes cinle sae eee eae eee ee eee 95 
Fig. 17. Glabella enlarged to three diameters, to show the granulose surface. 
PTY CHOPARTA: (1) VANNECTANS Sac ses 5225 otis see oe ee en eee 91 
Fig. 18. Glabella and fixed cheeks, enlarged to two diameters. 
1.0. 02h @ KE noe aes MEG EE CO OcOSEn Se aa Se asiacee ces aes raSaso apne G-sa eseeeekconccocd 00 
Fig. 19. Pygidium associated with the preceding, and also figs. 7 and 12, enlarged to two 
diameters. 
ASAPHUBS i enn elnistcinissince sie stin a snes ee ae Nos pete etl Oe ee 00 
Fig. 20. Strongly convex pygidium, associated with Asaphus Caribouensis. 
COLROPRION {MUN UA ao (a's = = <)aiain oom oto mo oil on eal eee raya ae ee ae 85 
Fig. 21. Enlargement of a portion of the tube to. four diameters, to show the arching of 
the striw over the longitudinal ridge on the side opposite the are of curvature. 
See plate xi, figs. 17, 17a. 
