PLATE XC. 



Figures magnified 500 diameters. 



Fig. 1. COSCINODISCUS EXCAVATUS, Grev. ; Prit., p. 829, 8, f. 26; Schin. 



At., 65, f. 1. North Carolina, New Jersey, etc. 

 " 2. " SECERNENDTJS, (Secernendus), A. S., Schm. At., 



114, f. 1. Maryland. 

 " 3. " RAIHATUS, Ehrb. Ahh., 1839, p. 148; Mik., 39, 3. 



f. 17; 35 A, 17, f. 6; Sill. .!., 1842, p. 95, 2, f. 14; 



S. B. I)., 3, f. 57 : Schm. At., 60, f. 5, 9, 6, 7, 10. 

 " 4. " WOODWARDIA, Enlens. Doubtfully this species 



and doubtfully N. Amer., Schrn. At., 61, f. 2; 



65, f. 2. 

 " 5. " FLORIDULUS, A. S., Schm. At., 113, f. 16. St. 



Monica. Rays not straight, but more or less 



curved, in concentric and excentric series of 



cellules. Hardly separable from C. Radiatus. 

 " 6. " LEPTOPUS, Grun. C. lineatus, var. V. H., 131, f. 



5. California. 

 Figs. 7, 8. " VELATUS, Schm. At., 62, f. 10-12, places these 



doubtfully to G. velatus. Virginia. May be 



varieties of C. Marginatus. 

 Fig. 9. IMPRESSUS, Grun. St. Monica. Center of cell 



somewhat depressed. 

 " 10. EXCENTRICUS, Ehrb. California. Schm. At., 58, 



f. 49. Figure rather finely lined. Might be 



more in hexagonal cells. 

 " 11. STTBVELATUS, so named provisionally by A. S. ; 



Schm. At., 65, f. 9. Monterey. 

 " 12. HETEROPORUS, var. Grun., Monterey; Schm. 



At., 61, f. 4, 5. 



