PLATE XIX. 



Figures magnified -500 diameters. 



Fig. 1. NAVICULA PROBABILIS, A. S., Schm. At., 50, f. 46, Camp. Bay. 



' 2. FORMOSA, Greg., T. M. S., 1856, p. 42, 5, f. 6, Schm. 



At., 50. f. 8-14. Only a var. of N. permagna, H. 

 L. S., Salt Lake; Neuse River, etc. 



" 3. PRODUCTA, a var., W. S., S. B. D., I, p. 51, 17, f. 144, 



Prit., p. 902, 7, f. 66; Schm. At., 49, f. 37-39, 50, f. 

 47. Marine. 



4. " HEXAPLA, A. S., Sehm. At., 50, f. 50, Oregon. 



" 5. AMPHIGOMPHUS, Ehrb. Mik., 6, 1, f. 20: 7, 1, f. 6, 



Rab. S. D., p. 38, 6, f. 47; Schm. At., 49, f. 31-34. 

 Maine, etc. 



" 6. I.INEARIS, Grun., 1860, p. 546, 1, f. 2, Schm. At., 50, 



f. 38; O'M. I. I)., p. 371, 31, f. 39. Gulf of Mexico. 



Figs. 7, 8. " MORMONORUM, Grun., Schm. At., 44, f. 24-26. Utah. 



Fig. 9. FIRMA, (var. subundnlata, Kg., K. B., p. 92, 21, f. 10, 



5. B. D., 16, f. 138; Schm. At., 49, f. 3, 14; var. 

 Subundulata, f. 16, Hudson River. 



" 10. FIRMA, typical form. 



11. FORMOSA, var. Same species, different form, as Fig. 



2, above. Utah, etc. 



" 12. " PRODUCTA, var., Schm. At., 50, f. 49; says fralic/i. 



Marine. 



13. AMPHIRHYNCHUS, Ehrb., K. B., p. 95, 4. f. 13; 2, f. 



11, S. B. D., I, p. 51, 16, f. 142; Prit., p. 901, 12, f. 



6. Fresh-water. 



14. " XODOSA, Ehrb. Mik., 17, 2, f. 12, 13, K. B., 28, f. 82; 



Rab., S. D.. 41, 6, f. 86; Schm. At,, 45, 56-58. 

 Fresh-water. 



" 15. PRODUCTA, var. nearer the typical form, Fig. 12, com- 



pare refs., Fig. 3. Marine. 



Figs. 16-19. BREBISSONII, Kg., K. B., 3, f. 49; 30, f. 39, Rab., S. 



D., 6, f. 54 ; Schm. At., 44, f. 16-19 ; Sm. Sp. T., No. 

 249, O'M. I. D., p. 350, 30, f. 24. Fresh- water. 



" 20,21. DIVERGENS, Ralfs., Prit., p. 896, Schm. At., 44, f. 6, 



14, 15, 42. Fresh-water. 



Fig. 22. " VACILLANS, A. S., Schm. At., 8, f. 61, V. H.,-9, f. !. 



Marine. 



" 23. AMPHISBAENA, Borg. Mik., 10, 1, f. 7 ; 7, 2, f. 5, etc., 



S. B. D., I, p. 51, 17, f. 147 ; Donk. B. D., p. 36, 5, 

 f. 13. Small form, fresh-water. 



