PLATE XCVII. 



Figures magnified 500 diameters 



Figs. 1, 2, (5, 11). BIDDULPHIA LAEVIS, Ehrb. Mik., 33, 15, f. 16; T. M. S., 



1859, p. 18, 2, f. 24-26, Sill. J., 1842, 2, f. 8. 

 A few of the many varieties widely dis- 

 tributed ; frequent along the sea board, 

 but also inland, salt marshes of Kansas, 

 Utah, etc. 



" 3,4. TURGIDTJS, W. S. ; Cerataulus ; Odontella, 



Ehrb. Spines of the valves wavy, not 

 rigid. V. H., 104, f. 1, 2; S. B. D., 62. f. 

 384; T. M. S., 1859, p. 17, 2, f. 23. 



" 5, (11). " POLYMORPHIC (Cerataulus), V. H., 104, f. 4, 



3. Odontella, polymorphus, Ehrb. Bid- 

 dulphia laevis, W. S. 



Pig. 6. " JOHNSONIANUS, Var. Grev.; Schm. At., 115, 



f. 15. 



" 7. TURGIDUS, Ehrb., Schm. At., 116, f. 2. Vide 



Figs. 3, 4, above. 



Figs. 8, (10). OVALIS, Cerataulus, A. S., Schm. At., 115, f. 7, 



and 115, f. 5. This diatom is not only finely 

 dotted but areolated like a Coscinodiscus. 



Fig. 9. CALIFORNICUS (Cerataulus), A. S. 



"11. " Vide Fig. 5. 



