2. Cymbella cuspidata, KTiiiir. P. smaller than the last, extremities
prominent, somewhat acuminate ; striæ indistinctly moniliform,
30 in -001". Length -0012" to -0031". v.s.
Kiitz. Bacill. iii. 40.
Fresh water. Quernmore near Lancaster, April 1852, Mr. Johnson. Wray
near Lancaster, Oct. 1852, 3Ir. G. Smith. Lough Mourne and Peterhead
Deposits. Premnay and Cantyre Peats. (Nova Scotia.)
Plate II. 22.
3. Cymbella affinis, Kiitz. V. elliptical-lanceolate, extremities
slightly produced ; striæ faint, 30 in -001". Length -0009" to
•0015". v.v.
Kiitz. Bacill. vi. 15. ad spec, authen. quæ dedit amie. De Brebisson.
Fresh water. Parham, Sussex, Feb. 1844, Mr. Jenner. Iford, Sussex,
April 1852, W. Sm. Marl, Co. Down, and Dolgelly Earth.
Supp. Plate XXX. 250. Frustule with endochrome. Frontispiece, fig. CCL.
4. Cymbella maculata, Larger segment of V. convex, smaller
with a slight inflation in the centre, extremities obtuse ; striæ 27 in
•001". Length -0008" to -0015". v.v.
Kiitz. Bacill. vi. 2?
Fresh water. River Frome near Wareham, Dorset, March 1848, W. Sm.
Cantyre Peat and Peterhead Deposits.
Plate II. 23.
5. Cymbella Helvetica, Kiitz. F. V. linear, slightly arched ; V.
elongated, segments as in the last, extremities acute ; striæ 24 in
•001". Length -0016" to -0031". v.v.
Kiitz. Bacill. vi. 13? Prit. Anim. xvii. 24-28.
Fresh water. River Ouse near Lewes, W. Sm. Peterhead Deposit. Near
Aberdeen, Dr. Dickie.
Plate II. 24.
6. CymbeUa Scotica, n. sp. V. narrow, elongated, smaller segment
straight, extremities acute ; striæ 32 in -OOl". Length -0012" to
•0027". v.s.
Fresh water. Pass of Killiecrankie, very plentiful, Mr. P. Grant. Dolgelly
Plate II. 25.
G en u s 4. AM PH O RA , Ehr.
Frustules free, or adherent ; valves cymbiform, with a central marginal
nodule.
The valves in this genus are exceedingly convex, closely resembling
those of Epithemia rupestris, and the section of the frustule is the
same as that which I have described under that species. I t is probable
that most of the Amphoree are at first adherent, hut they are
usually found detached, and sparingly diffused among other Algæ.
1 . Amphora ovalis, Kütz. F. V. elliptical, internal margin of V.
inflated at the nodule; striæ moniliform, distinct, 24 in -OOl".
Length -0012" to -0038". v.v.
Kütz. Bacill. V. 25 & 39. Nav. Amphora, Ehr. Inf. xiv. 3. Prit. Anim.
iii. 153.
Presh water: frequent. Lewes, April 1852, W. Srn. Lough Mourne Deposit.
Peterhead Deposit, &c.
Plate II. 2 6 . Frustule with endochrome. Frontispiece fig. XXVI.
2. Amphora affinis, Kütz. F. V. oblong, with round or truncate
extremities ; striæ distinct, 27 in -OOl". Length -0016" to -0022".
v.v.
Kütz. Bacill. XXX. 6 6 .
Brackish water. Near Lewes, Sussex, Feb. 1852, W. Sm.
Plate II. 2 7 .
3. Amphora hyalina, Kütz. F.V. elliptical, acute ; V. imperfectly
siliceous, longitudinally rugose; striæ obscure. Length -0021"
to -0032". v.v.
Kiitz. Bacill. XXX. 1 8 .
Brackish water. Coast of Sussex, Nov. 1850, TV. Sm. Near Lancaster,
Mr. Johnson.
Plate II. 28.
4. Amphora salina, n. sp. F. V. elliptical, truncate, extremities
c 2