PLATE XCI. 

 Figures magnified 500 diameters. 



Fig. 1. ARACHNOIDISCUS EHRENBERGII, Bail., Wilkes Ex., p. 174, 9, 



f. 9; S, B. 'D., 31, f. 256; Schm. At., 08, f. 

 1 ; 73, f. 1. 



" EHRENBERGII, var. Moutereyanu, Grun. ; 



Schm. At., 68, f. 2. 



" 3. EHRENBERGII, var. Californica, A. S., Schm. 



At., 73, f. 1. 



4. EHRENBERGII, var. Californica, Weissfl. ; 



Schm. At., 68, f. 3. 



" 5. " GREVILL.EANUS, Hardm. ; Schm. At., 68, f. 



5. Monterey. 



" 6. " INDICUS, Ehrb., var.; Sehm. At., 73, f. 2; 



Mik., 36, f. 24. 



Figs. 7, (10, 11). INDICUS, vars.; Schm. At., 68, f. 6,9, 10. Cen- 



ter less filled ; hardly a rosette as shown 

 in Figs. 10 and 11. 



" 8,9. " ORNATUS, var. Montereyana; A. S., Schm. 



At. 73, f. 7, 9. Rosette does not show blank 

 center large enough in either figure ; it is 

 quite apparent on the valve, H. L. S. MSS. 



