PLATE CLI. 



FIGS. PAGE 



1. Staurastrum Cerastes Lund. X 520 . .141 



2-5. St. elongatum Barker. 2 and 4, X 520 ; 3, ver- 

 tical view, X 520 ; 5, basal view of semicell, X 

 520 . . ' . . . 156 



6. St. barbaricum W. & G. S. W. X 520. . 157 



7-8. St. verticillatum Arch. 7, X 520 ; 8*, vertical 



view, X 510 . . . .155 



9-11. St. vestitum Rail's. 9, x 500; 10, vertical view 



X 500 ; 11, X 430 . . . 158 



