PLATE LXXV. 

 Figures magnified 500 diameters. 



Fig. 1. AULACODISOUS MCELLERI, A. S. Schm. At., 33, f. 14. Notting- 



ham, Md. 



" 2. DECORTJS, (related to), Schm. At.,33, f.9. Mon- 



terey. 

 STICTODISOUS HARDMANIANUS, forma minor. 



SIMPLEX, A. S., Sci-m. At., 74, f. 11. San Fran- 

 cisco, C'al. Appears very nearly related to 

 Aracknodiscus. 



Fiirs. 5, is. " ( 'AT.IFORNICUS, vars. Grev.; Schm. At., 74, f. 9. 



Fig. 7. var. ecostata, Grun.; Schm. At., 



74, f. 6, 7. 

 (ALJFORNICUS, Grev. ; Los Angeles, Schm. At., 



74, f. 4. 



Figs. 9, 10. KITTONIANUS, Schm. At., 74, f. 16-18. Notting- 



ham, Md. 

 Fig. 11. TRICERATIUM CINNAMOMIUM, (Cestodiscus) Grev. M. J., 1S63, 



p. 232, 10, f. 12. 



" 12. COSMIODISCUS TENUIS, Grev.; V. H., 125, f. 13. 



Figs. 13-1."). STICTODISCUS, A. Schm. determines these as inner plates of 

 , Stictodiscus, snch as occur frequently with 



Asteromphalus and Ast&rola/mpra and have 

 given rise to a number of spurious species. 

 Grunow determines these three forms to be 

 plates of Melosira cleavigera. 

 Fig. 16. EUNOTOGRAMMA DEBILIS, Grun.; Cimip. Bay. V. H., 126, f. 17. 



May be with, or without the opening. 



Figs. 17-19. LAEVIS, Grun.; V. H., 126, f. 6, 7, 9. N. C., 



Fla. 



