PLATE XXVIII. 



Figures 3, 7, 10, 12 magnified 150 diameters ; others 500 diameters. 



Page. 



Fig. 1. EUASTETJM CKASSUM, . . . 106 



" 2. " " semi-cells of very large form, . 106 



" 3. " " transverse view of semi-cell, , . 106 



" 4. EUASTKUM OENATUM, a form of " E. crassum," . . 106 



Figs. 5, 6. EnASTRCM oblongum, two forms, . . . 106 



Fig. 7. " " transverse view of semi-cell, . 106 



Figs. 8, 9. EuASARUM ansatitm, two forms, . . . 109 



Fig. 10. " " transverse view of semi-cell, . 109 



Figs. 11, 12. Edbastrum affine, front and transverse views, . . 110 



