Navicula plioenicenteron Ehr., Die Tnfus. p. 175. t. xlii.
fig. 1. /3.
liai). Cheshunt: A. II. H. — Var. ri. Gardener S treet:
Air. Jenner.
I t is possible that the variety ri of Ehrenherg, which is that
here described under the name of N. phoenicenteron, is really
distinct. The frustule is not transversely striated, hut several
longitudinal lines may frequently be noticed running along
the centre of each.
2. N avícula palea Ilass.
Plate CH. Pig. 10.
Char. Frustules small, smooth. In front view attenuated,
with truncate extremities ; in side aspect lanceolate.
Navicula gracilis Ehr., Die Infus. p. 176. t. xiii. fig. 2.
Frustulia gracilis Jenner, in Flora of Tunbridge Wells,
p. 204. Cgmhella arenacea Breb. et Godey.
Hab. Cheshunt : A. II. II. In the great bog near Forest
Bow ; bogs at Fisher’s Castle, &c. : Air. Jenner.
This species resembles N. phoenicenteron in miniature.
3. N avícula ampiiisbæna Bory.
Plate CH. Fig. 5.
Char. Frustules elongated. In front view quadrangular,
loith straight sides ; in lateral aspect oval, prolonged at
each end into a blunt process.
Navicula amplùshæna Bory, Encycl. Méth. 1824. Navi-
cula amphisbæna Turpin, Diction, des Sc. Nat. 1828.
N. ventricosa, Abhandl. der Akademie d. Wissensch. zu
Berlin, 1830, p. 67. N. amphisbæna, Abhandl. &c.
1833 (1832), p. 254. Frustulia cuspidata Kütz., L in næa,
1833, p. 549. t. xiv. fig. 26. N. amphisbæna. Die
Infus. p. 178. t. xiii. f. 7. Cymhella appendiculata
Godey et Breb.
Hah. Cheshunt: A. II. II. Aberdeen: Dr. Dickie.
A very well marked species.
4. N avícula platystoma Ehr.
Plate C II. Fig. 6.
Char. Frustules elongated, quadrangular, with straight sides,
rostrated at each end.
Hah. Che sh u n t: A. II. II.
Die Infus. p. 178. t. xiii. fig. 8.
A distinct and not uncommon species.
b. Frustules striated.
5. N avícula nodosa Ehr.
Plate C II. Fig. 7.
Char. Frustules small, in side view thrice undulated, rostrated
at each extremity.
Die Infus. t. xiii. fig. 9. Frustulia nodosa ? Jenner, in
PI. of Tunbridge Wells, p. 204.
llah. On Ashdown Forest, near Forest Bow, between
Gardener Street and Hailsham, &c. : Air. Jenner.
Mr. Jenner remarks that his specimens agree with Ehrenberg’s
description and figures in every respect save that tlic
frustules were striated. I t is probable tha t Ehrenherg
overlooked the striæ, and tha t these are always present.
6. N avícula inæqualis Ehr.
P late C II. Fig. 13.
Char. Frustules in front view attenuated, towards each end
truncate; in side aspect unequal.
Navicula inæqualis, Bericht. der Akademie d. Wissensch.
zn Berlin, 1836, p. 53. ; Die Infus. p. 184. t. xiii. f. 18.