PLATE CLII. 



FIGS. PAGE 



1-2. Staurastrum Ophiura Lund. 1, X 520 ; 2*, x 



510 . . . . . 153 



3-4.' St. Ophiura var. cambricum W. & Gr. S. W. 3, X 



430 ; 4*, vertical view, X 510 . . 154 



5-6. St. vestitum Ealfs. 5, X 520 ; 6, zygospore, X 500 



(after Wolle) . . .158 



7-8. St. vestitum. var. semivestitum West. X 520 160 



