w
• i l
3. Asterionella Bleakeleyii, n. sp. Frustules linear, enlarged at
the base. Length of frustule -0022". v.s.
Marine. Harwich, May 1853, 3Ir. Bleakeley.
The meagreness of the above descriptions, the fullest I can give from the
dried specimens in my hands, leaves much to be done by more fortunate
observers.
I am, however, tolerably certain of the distinctness of the three forms,
A. Ba/fsii being obviously different from the other two, and the habitat of
A. Bleakeleyii placing it apart from A. formosa, to which it otherwise bears a
close resemblance.
A P P E N D I X ,
A.
Since the publication of the first volume of the Synopsis, the following
British forms belonging to genera therein described have been
discovered or detected by various observers, and seem entitled to
rank a.s 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 ; striæ indistinct/ 42 in -001". Length -0008"
to -0015". v.v.
Eunotia Camelusl, Ehr. in Grev. Ann. 2nd ser. vol. 15. pl. ix. I.
Fresh water. Braemar, August 1854, Br. Balfour. Fell-end near J.an-
caster, Aug. and Oct. 1854, Mr. Johnson. Arran, July 1854, Br. 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 ; striæ obscure. Length -0005". Breadth
of valve -0002". v.s.
Ehr. in Kiitz. Bacill. xxix. 60 ; Microg. xxxix. ii. 51. xv. B. 29. Grev. Ann.
2nd ser. vol. 15. pl. ix. 2. Greg. Mic. Journ. vol. 4. pi. i. 1. Eunotia
crenulata, Bréb. ad specimina quæ 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