O’Mrara—Leport on the Irish Diatomacee. 313 
Synedra Smith, N.S. Fresh water. 
Frustules small; on front view quadrangular; on side view nar- 
row, linear; accuminate at the ends; strie short. (Pl. 28, fig. 
42. 
hats Vvaucvherce, Wit ome... D. Vols 1:, p: Te; Pl) “x1, 
fig. 99, who identifies the species with that so named by Kitzing, Bac., 
p. 65, T. iv., fig. 4, 1, 2a, 83; and so far as the description of it is 
concerned, not without warrant: but although in some respects the 
figures cited seem to agree with the form under notice, in other re- 
spects there is such a difference as to cast a doubt on the correctness 
of the identification. Kiitzing represents the striation in his form as 
pervious, whereas in that figured and described, by Smith the striz 
are marginal and very short. Rabenhorst describes and figures a form 
under the name of 8. vaucherie ; but although from the description it 
might fairly be supposed to be the same as the present form, the figure 
renders the identity more than doubtful; Stussw. Diat., p. 55, T. iv., 
fig. 15. Again, Grunow describes a form as identical with Kiitzing’s 
Synedra vaucherize ; Verhand. der K. K. Zool. Bot. Gesel., Band xi.., 
1862, p. 393, T. v., fig. 9, which seems to differ widely from Kitzing’s 
figure, as well from that so named by Wm. Smith. He remarks :— 
‘‘The species here referred to, which exhibits a decided relationship 
to Synedra pulchella, I regarded for a long time as the identical 
Synedra vaucheriz of Kiitzing and recently had my impression on the 
subject confirmed through means of some specimens of De Brébisson’s, 
_ kindly sent to me by Professor A. Braun. I find Smith’s figure 
widely different from Synedra vaucherie, Kiitz., which might much 
rather be regarded as a form of Synedra affinis, although Synedra 
vaucheriz also possesses a tolerably broad unstriate space between 
the striz, but in the description I find no allusion to the unstriate 
very fine ring-formed-pseudo-nodule.”? These remarks make it obvious 
that it is impossible to identify Smith’s form with Synedra vaucheria, 
Kiitz., from which it differs considerably. I have therefore adopted 
a new specific name, that of Synedra Smithii. 
Tacumshane, Co. Wexford. River at Port-na-Crush, Co. Donegal. 
Malahide, Portmarnock, St. Fenton’s Well, Sutton, Co. Dublin. 
(g.) Stri@ obsolete. 
Synedra debilis, (Kutz.) Fresh water. 
Frustules very minute ; on front view regularly quadrangular ; on 
side view elliptical-lanceolate. (Plate 28, fig. 43.) 
Kitz. Bac., p. 65, T. mi., fig. 45. Ralfs, in Pritch., p. 787.— 
Synedra radians, var. debilis, Rab. Fl. Eur., sect. 1, p. 136. 
Twyford Lake, near Athlone, Co. Westmeath. River Dour, 
Co. Cork. 
