O'Meaua — Hejjort on the Irish Diatomacecs. 313 



St/neira Smithii, IT. S. Fresh, water. 



Frustules small ; on front view quadrangular ; on side \T.ew nar- 

 row, linear ; accuniinate at tlie ends ; striae short. (PI. 28, fig. 

 42.) 



Synedra vauclierise, Wm. Sm., B. D., Yol. i., p. 73, PI. xi., 

 fig. 99, who identifies the species with that so named by Kiitzing, Bac, 

 p. 65, T. iy., fig. 4, 1, 2«, 3 ; 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 

 peryious, whereas in that figured and described by Smith the strise 

 are marginal and yeiy short. Eabenhorst describes and figures a form 

 under the name of S. yaucherise ; 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 ; Siissw. Diat., p. 55, T. iv., 

 fig. 15. Again, Grunow describes a form as identical with Kiitzing's 

 Synedra yaucheriae ; Yerhand. der K. K. Zool. Bot. Gesel., Band xii., 

 1862, p. 393, T. y., fig. 9, which, seems to differ widely from Kiitzing'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 yaucheriae of Kiitzing and recently had my impression on th.e 

 subject confirmed through, means of some specimens of De Brebisson's, 

 kindly sent to me by Professor A. Braun. I find Smith's figure 

 widely different from Synedra yaucheriae, Kiitz., which might much, 

 rather be regarded as a form of Synedra affinis, although Synedra 

 yaucheriae also possesses a tolerably broad unstriate space between 

 the stiiae, but in the description I find no allusion to the unstriate 

 yery fine ring-formed-pseudo-nodule." These remarks make it obyious 

 that it is impossible to identify Smith's form with Synedra yaucherite, 

 Kiitz., from which it differs considerably. I haye therefore adopted 

 a new specific name, that of Synedra Smithii. 



Tacumshane, Co. "Wexford. Eiyer at Port-na- Crush, Co. Donegal. 

 Malahide, Portmarnock, St. Fenton's Well, Sutton, Co. Dublin. 



(g.) Strim obsolete. 



Synedra delilis, (Kiitz.) Fresh, water. 



Frustules yery minute ; on fi'ont yiew regularly quadrangular ; on 

 side yiew elliptical-lanceolate. (Plate 28, fig. 43.) 



Kiitz. Bac, p. 65, T. lii., fig. 45. Ralfs, in Pritch., p. 787.— 

 Synedra radians, yar. debilis, Bab. Fl. Eur., sect. 1, p. 136, 



Twyford Lake, near Athlone, Co. "Westmeath. Riyer Doui-, 

 Co. Cork. 



