8 
10. Campylodiscus parvulus W.:Smith.—Hab. On marine alge from 
Newport, R.I., 5. 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 Hhr.—Hab. Entire coast, on alge and on mud. 
Common, and presenting a great range of outline and size. 
15. Surirella craticula EHhr.—Hab. Delaware river mud. Rice field 
mud, Savannah. 
16. Nitzschia bilobata W. Smith.—Huab. Bridgeport, Conn., harbor ; ad- 
herent to roots of harbor grass. Very rare. 
17. Nitzschia closterium W. Smith.—Hab. Marshes near Port Penn, 
Del. On alge 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. 
The 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 
strie, and the prominence of the puncta, might be confounded with the larger | 
frustules of Tryblionella constricta. 
20. Nitzschia reversa W. Smith.—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 alge at Stonington In- 
let, L. I. Wilming'on marshes, Del., Mr. Febiger. Common, 
Several varieties of this species are found, in one of which the markings 
on the keel 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 acommon rice field species. The common variety in this 
country is shewn in Pl. IL. f. 6. 
25. Navicula Jennerii W. Smith.—Hab. St. Sebastian river, St. Augus- 
tine, Florida; in mud. Rare. 
