205 



The following are new to Britain, or now first distinguished from 

 others : — 



1. Epithemia gibberula. 



2. Eunotia bigibba, Kiitg. 



3. „ Camelus, Kiitz. 



4. „ depressa, Kiitz. 



5. Navicula laevissima. 



6. „ Trochus. 



7. Cocconema gibbum. 



8. Himantidium exiguum, Brib. 



Of these 8 species, figures were exhibited ; and in the case of 

 Eunotia bigibba a number of striking varieties were figured, and 

 compared with several varieties of Himantidium bidens, with which, 

 it had hitherto been confounded. 



The author then proceeded to describe and illustrate by figures 

 the following species, most of which are new to science :- — 



