PLATE CVII. 



Figures magnified 500 diameters. 



Figs. 1, 2. AMPHIPRAKA NEREIS, Lewis. Atlantic sea-board, Narra- 



gansett. Figures too large, H. L. S. Length 

 of valve .002", (S) .0045". N. and R. Sp., 6, 

 1, f. 6. 



" 3, 4. " CONSERTA, Lewis N. and R., 1, f. 5. Prof. 



Smith writes : " I believe I am the only one 

 who has specimens of this diatom ; it is 

 scarcely siliceous. 



Fig. 5. OOSTATA, O'Meary, Irish; erroneously en- 



rolled as N. American. M. J., Vol. IX, N. 

 S., 12, f. . 



Figs. r>, i'.i). TRICERATUM MONTEREYI, Brightw. Copied from fossil dia- 

 toms of New Zealand, (PI. XI, f. 25,) to 

 show the extreme convexity of the termi- 

 nal valve of a frustule. 



Fig. 7. SURIRELLA PULCHRA, Lewis N. and R.,-p. 4, 1, f. 1. Allied 



to S. faMuosa and <S.' eximia. St. Mary's 

 River, Ga.. salt marsh, Florida. Length ol 

 valve .005"-.009". 

 " 8. MASTOGLOIA ELEGANS, Lewis, p. H46; Proc. A. N. Sc., PL 



3, f. <'. 



" 9. TRICERATIUM MONTEREYI, vide above Fig. 0. 



" 10. MASTOGLOIA ANGULATA, Lewis N. and R., PI. 2, f. 4. The 



granules are really arranged in regular 

 quincunx order. Atlantic City, Rock- 

 away, etc. 



" 11. " SUBMARGINATA, Cleve. and Gr., N., and S. K. 



D., 1, f. 2. The figure of this diatom is 

 iliU'erently represented in size by different 

 authors ; it is probably only about half as 

 large as here represented. 



