PLATE LXXXVIII. 



Figures magnified 500 diameters. 



Fig. 1. AuijAConiseus CRUX, Ehrb.; Richmond, Va. Areolation (cellules) 



hexagonal. Schm. At., 124, f. 1. 



" 2. KITTONII, Arnott. San Francisco. Schm. At., 36, 



f. 3 = A. Ehrenbergii, Janisch. Monterey. 



" 3. THUMII, A. S. The cellules are not simply round 



and smooth ; the diatom is composed of two 

 plates, the upper one is perforated and the other 

 dotted all over with granules. St. Monica. Schm. 

 At., 108, f. 8. 



' 4. OREGONUS, Bailey. Areolation more or less hex- 



agonal. 



" 5. CALIFORNICA, Schm. At., 34, f. 4, 5. 



" 6. " OREGONUS, smaller var. of Fig. 4. 



" 7. CIRCUMDATUS, A. S., Schm. At.. 35, f. 5. California. 



" is. PROBABILIS, A. S., Schm. At., 36, f. 15. Monterey. 



Cellules arranged more or less in circles around 

 the middle. Nearly akin to A. Brownii. 



" 9. SOLLITIANUS. Nor. ; Schm. At., 33, f. 10. Notting- 



ham, Md. Surface dotted with very small 

 prickles. 



" 10. BROWNEI, Norm. Monterey. Schm. At., 105, f. (i; 



hardly separable from A. probabiiis, Fig. 8. 



" 11. KINKERI, A. S., Schm. At., 106, f. 45. St. Monica. 



Possibly a var. of A. crux. 



