66 PROCEEDINGS OF THE ACADEMY OP 



10. Campylodiscus par villus W. Smith. Hab. On marine algae from 

 Newport, R. I., S. Powel. New London harbor mud. St. Augustine, Florida. 

 The valves on the American variety, as far as met with, always have the 

 valves at right angles to each other. Rare. 



11. Campylodiscus Ralfsii W. Smith. Hab. Black Rock Harbor mud. 

 Connecticut river mud. Rare. 



12. Campylodiscus Hodgsonii W. Smith. Hab. Mud from Savannah 

 river. Rare. 



13. Campylodiscus spiralis W. Smith. Hab. Ogeechee river, Ga. Savan- 

 nah river. This fresh water species obtrudes on the above localities, also on 

 the blue clay, Delaware river. 



14. Surirella fastuosa Ehr. Hab. Entire coast, on algae and on mud. 

 Common, and presenting a great range of outline and size. 



15. Surirella craticula Ehr. Hab. Delaware river mud. Rice field 

 mud, Savannah. 



16. Nitzschia bilobata W. Smith. Hab. Bridgeport, Conn., harbor ; ad- 

 herent to roots of harbor grass. Very rare. 



17. Nitzschia clost'erium W. Smith. Hab. Marshes near Port Penn, 

 Del. On algae at Stonington, Conn. Rare. 



18. Nitzschia spathulata W. Smith = N. hyalina (Gregory.) Hab. 

 Salt marshes along the railroad at Atlantic, N. J. Salt marsh, Cape May, Mr. 

 Febiger. 



Tbe American variety is smaller than the foreign. 



19. Nitzschia panduriformis Gregory. Hab. St. Mary's river, mud 

 from oysters. Rare. 



This beautiful species varies a good deal in size and somewhat in outline. 

 The smaller specimens, but for the greater sharpness and coarseness of the 

 striae, and the prominence of the puncta, might be confounded with the larger 

 frustules of Tryblionella constricta. 



20. Nitzschia r e v e r s a W. Sm.ith. Hab. St. George's Marsh, near Port 

 Penn, Del. Marshes near Wilmington, Mr. Febiger. Rare. 



21. Nitzschia amphioxys W. Smith. Hab. Delaware river mud, 

 marshes near Delaware City, Mr. Febiger. 



22. Nitzschia angularis W. Smith. Hab. Delaware river mud. Mud 

 from Bannister's creek, Rockaway, L. I. 



23. Amphiprora paludosa W. Smith. Hab. On algae at Stonington In- 

 let, L. I. Wilmington marshes, Del., Mr. Febiger. Common. 



Several varieties of this species are found, in one of which the markings 

 on the ieel are entirely wanting. Atlantic salt marshes. 



24. Navicula trinodis W. Smith. Hab. Large rivers and brackish and 

 fresh water marshes along the entire Atlantic coast. At Northam's Pond, 

 brackish, Newport, R. I., Mr. Powel. Very abundant. 



This species answers so fully to the description of N. trinodis Smith, that 

 their identity can scarcely be questioned. A southern variety from St. Mary's 

 river attains a much larger size, and the ends are often considerably produced. 

 N. trinodis is a common rice field species. The common variety in this 

 country is shewn in PI. II. f. 6. 



25. Navicula Jennerii W. Smith. Hab. St. Sebastian river, St. Augus- 

 tine, Florida ; in mud. Rare. 



[March,, 



