APPENDIX. 



A. 



Since the publication of the first volume of the Synopsis, the fol- 

 lowing British forms belonging to genera therein described have been 

 discovered or detected by various observers, and seem entitled to 

 rank as distinct species, or as well-marked varieties. 



1. Eunotia bidentula, W. Sm. Frustule direct; valve with two 

 prominent, acute, or rounded dorsal ridges ; basal margin straight, 

 extremities produced ; striae indistinct, 42 in *001". Length *0008" 

 to -0015". v.v. 



Eunotia Camelusl, Ehr. in Grev. Ann. 2nd ser. vol. 15. pi. ix. 1. 



Freshwater. Braemar, August 1854, Br. Balfour. Fell-end near Lan- 

 caster, Aug. and Oct. 1854, Mr. Johnson. Arran, July 1854, Dr. Arnott. 

 Barley Lough near Glengariffe, Co. Cork, June 1855, W. Sm. 



The figure in the ' Microgeologie,' xxxix. 15, of E. Camelus, Ehr., shows 

 that the present cannot be that species. 



2. Eunotia tridentula, Ehr. Frustule arcuate; valve with three 

 slight dorsal elevations ; striae obscure. Length "0005". Breadth 

 of valve -0002". v.s. 



Ehr. in Kiitz. Bacill. xxix. 60 ; Microg. xxxix. ii. 5 1 . xv. B. 29. Grev. Ann. 

 2nd ser. vol. 15. pi. ix. 2. Greg. Mic. Journ. vol. 4. pi. i. 1. Eunotia 

 crenulata, Breb. ad specimina quae misit cl. Auctor. 



Freshwater. Fell-end, Lancashire, May 1851, Mr. Johnson. Braemar, 

 Aug. 1854, Br. Balfour. 



3. Eunotia quaternaria, Ehr. Frustule arcuate; valve with four 



g 2 



