OF BRITISH FRESH-WATER DIATOMACE^. 3 



never, as many other forms do, in crowds together. But this 

 consideration shows the necessity of minute search, without 

 which many of the scattered forms would escape observation. 

 Many similar examples might be adduced. 



It would be intolerably tedious to give a list of all the species 

 observed in these gatherings, of which I have examined, more 

 or less minutely, upwards of 200. I may state that, with few 

 exceptions, I have met with all the known British fresh water 

 species, and that I have found various new localities for many 

 rare and curious forms. 



Few, if any, of the new species which have occurred, are 

 confined to one locality ; most of them have been found in 

 several and these widely distant stations. 



These new species may be conveniently arranged in three 

 sections : 1. Those already described by foreign naturalists, 

 but now first detected as British forms. 2. Those which, 

 although I have myself recognised them as entirely new forms, 

 have been also, either about the same time or subsequently, 

 observed by others. Although these are still unpublished MS. 

 species, and in many cases, my own observations were by 

 much the earliest, yet as I find that these forms have been 

 named by Mr. Smith, I adopt his names, to avoid the confu- 

 sion arising from synonyms. 3. Species which, so far as I 

 can discover, have nowhere as yet been described or figured. 



I. Species, now first found as British, but known to foreign 

 authors. 



1. Eunotia tridentula, Ehr., fig. 1, PI. I.* — Banffshire, R. 

 Findhorn. 



2. NavicuIafoUis, Ehr. — Lochleven, (qu. ? Trochus?) 



3. JV. dubia, Kiitz, — Elgin, Lochleven. 



4. JV. bacillum, Ehr. — Lochleven, 



5. Pinnularia nodosa, Kiitz. (Legumen, Ehr.) — Elgin, 

 Elchies, &c. 



6. P. megaloptera, Ehr. — ^Benrinnes, Elgin. 



7. P. dactylus, Ehr. — Benrinnes, Elgin. 



8. P. pygmaea, Ehr. {Nana, W. G.) — Near Edinburgh. 



9. Stauroneis Legumen, Kiitz. — Elgin, R. Findhorn, Dud- 

 dingston Loch. 



10. S. ventricosa, Kiitz, — Elchies, Elgin. 



11. Cocconema cormiturn, Ehr.? — Lochleven. 



12. Gomphenema subtile, Ehr,, Elgin. — denshire sand. 



13. Meloma distans, Ehr. (Gallionella). — Elgin, Elchies, 

 Lochleven. 



I do not give these as in all cases absolutely distinct species, 



* The species are numbered to correspond with the figures in Plate I. 



B 2 



