O70 Proceedings of the Royal Irish Academy. 
Navicula producta, (Wm. Sm.) Fresh water. 
Valve linear, elliptical; ends produced and Aiea capitate ; 
transverse strice distinct ; linear- -punctate parallel; longitudinal strize 
distinct ; intermediate free space very narrow ; length ‘0040, breadth 
"0010. (Plate 31, fig. 35.) 
Wm, Sm., B.D. Vol. 1, p. ol, PE xu, te 14e6 Baler 
Pritch., p. 902, Pl. vii., fig. 62. Grunow, Verhand. der K. K. Zool. 
Bot. Gesell., Band x., 1860, p. 543.—Navicula affinis, var. producta, 
Rab. Fl. Eur. Alg., sect. i., p. 197. 
Botanical Gardens of Trinity College, Dublin. Lower Lake, Killar- 
ney, Co. Kerry. Sub-peat Deposit, Dromore, Co. Down. 
Navicula coccononerformis, (Gregory). Fresh water. 
Valve elliptical ; transverse striz very fine, linear slightly radiate ; 
longitudinal strize more obvious; intermediate free space narrow, 
lanceolate; length 0016, breadth -0008. (Plate 31, fig. 36.) 
None of the authors J am acquainted with have alluded to the 
longitudinal strie, which notwithstanding are very obvious when the 
valve is observed in a dry state. When mounted in balsam, they are 
quite undistinguishable, except with very high powers, and with good 
ilumination. 
Gregory; 'Q.J> Mo 8.71856, p. 6, Pier, ne 22) Win Sint beep 
Vol.\i1., ‘‘p: 92: “Ralis, im’ Pritch., p, 896." 'Grunow, Verkaud: der 
K. K. Zool. Bot. Gesell., Band x., 1860, p. 550, T. iv., fig. 9. Rab. 
Fl. Eur. Alg., sect. 1, fig. 186 and p. 189. Donkin, N. H. Brit. Diat., 
p. 22, Pl. iu., fig. 11. lLagerstedt, Sdtv. Diat. fran Spetsbergen och 
Beeren Eiland, p. 32, T. i1., fig. 8. 
Lough Mask, near Toumakeady, Co. Mayo. Lough Mourne 
deposit. 
Tavicula Kotzchyt, (Grunow). Fresh water. 
Valve small, elliptical, lanceolate; ends slightly produced, and 
occasionally slightly constricted; central nodule large and quadrangu- 
lar; striz fine, linear, in the middle more distinct than towards the 
ends, radiate ; longitt adinal strive distinct ; length -00138, breadth °0005. 
Grunow, Verhand. der K. K. Zool. Bot. “Gesell., Band x, 1800, 
p. 538, T. iv., fig. 12. This author represents the strie as moniliform, 
but in the few forms that came under my notice I could not verify 
this representation. The longitudinal striz are not noticed by Grunow, 
but with careful manipulation they were very apparent in my speci- 
mens. Grunow gives three figures of this species; of these the short- 
est and broadest, and that in which the strie are not so distinct is the 
form with which my specimens are most in accordance.—Navicula 
Kotschyana, Rab. Fl. Eur. Alg., sect. 1., p. 193. 
Lough Mask, near Tourmakealy, Co. Mayo. 
