22 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 149 



Figs. 21-26. Xenambonites cf. X. revelatus Williams. 21, 23, 25. Brachial, 

 pedicle, and anterior views, X 5, complete but immature specimen, USNM 

 145344 ; 22, fragmentary specimen, X 5, showing peculiar distinctive car- 

 dinalia, USNM 145345; 24, 26, exterior and interior of brachial valve, 

 X 4, USNM 145346. 



Plate 3 

 (All specimens from USGS colln. D1072 CO) 



Figs. 1-5. Dicoelosia jonesridgensis Ross and Dutro, n. sp. 1, 2, 3, 5. Brachial, 

 left lateral, pedicle, and anterior views of complete specimen, X 5, holotype, 

 USNM 145347; 4, brachial interior, X 5, paratype, USNM 145348. 



Figs. 6-10, 14, 17, 20. Whitfieldella? sp. 6, 8, 10. Brachial, pedicle, and left 

 lateral views, X 5, of a specimen possibly referable to Glassia, USNM 

 145349 ; 7, 9, interior and exterior views, X 2, damaged brachial valve, 

 USNM 145350; 14, 17, 20, brachial, pedicle, and left lateral views, X 4, 

 USNM 145351. 



Figs. 11, 12. Genus undetermined B. Exterior and interior views, X 2, frag- 

 mentary brachial valve, USNM 145352. 



Figs. 13, 15, 16. Genus undetermined A. Anterior, brachial, and pedicle views, 

 X5, USNM 145353. 



Figs. 18, 19. Ptychoglyptus? cf. P?. pauciradiatus Reed. Brachial and pedicle 

 views, X 2, of the only specimen obtained, USNM 145354. 



Fig. 21. Christiania sp. Brachial interior, X 2, fragmentary specimen, USNM 

 145355. 



