O’Mrara—Report on the Irish Diatomacee. 363 
Navicula amphisbena, (Bory). Fresh water. 
Valve broadly elliptical, with produced capitate ends, longitudinal 
sulci close to the margin; intermediate free space lanceolate, broad 
in the middie. Strie fine, linear, close, radiate; length ‘0035, 
breadth -2013. (Pl. 31, fig. 18.) 
Kitz. Bac., p. 95, T. i., figs. 41 and 42. This author regards 
the species as identical with Navicula amphisbena, Bory, 1824, to 
whom, therefore, it should be attributed. Wm. Sm., B. D., Vol.i., p. 
51, PL xvi, fig. 147. Ralfs, in Pritch., p. 899, Pl. vu., fig. 72. Rab. 
Siissw. Diat., p. 40,2. wmyig. 66: Grunow, Verhand. der K. K. 
Zool. Bot. Gesell., Band x., 1860, p. 36. Heiber rg, De Danske Diat., 
p- 82. Cleve, Om Svenska och Norska Diat., p. 227. Donkin, N. H. 
Brit. Diat., p. 36, Pl. v. fig. 13. 
River Dodder, Dundrum, Blackrock, Malahide, Co. Dublin. River 
Bann, Coleraine, Bellarena, Co. Derry. Caumlough, near Tralee. 
Lough Gill, Co. Kerry. Breaches, near Newcastle, Co. Wicklow. 
Tacumshane, Co. Wexford. 
Navicula subsalina, (Ehr.) Btackish water. 
In all respects resembling Navicula amphisbena, except that the 
ends are not capitate, nor so much produced. 
Donkin, N. H. Brit. Diat., p. 24, Pl. iv., fig. 2.—Navicula am- 
phisbeena, var. 8. Wm. Sm., B.D., Vol.i., p. 51; Pl. xvii., fig. 147 B. 
The last-named author attributes the species to Ehrenberg. Cleve, 
Diatoms from Arctic Sea, p. 18. This form occurs freque ently, eed 
with Navicula amphisbena, in places accessible to marine influences, 
but I have never found it in perfectly fresh water. So that, with 
Donkin, I am disposed to consider it may be a distinct species. 
Tacumshane, Co. Wexford. Breaches, Co. Wicklow. Caumlough, 
near Tralee. Lough Gill, Co. Kerry. Malahide, Co. Dublin. 
Navicula elegans, (Wm. Sm.) Marine or brackish water. 
Valve elliptical, lanceolate; longitudinal sulci marginal. Strize 
distinct, linear, convergent in the middle, afterwards radiate; inter- 
mediate free space narrow, except in the middle, where it expands 
considerably ; length about ‘0038, breadth about 00065. (PI. 31, 
fig. 19.) 
Wm. Sm. B. D., Vol. i., p. 49. Pl. xvi. fig. 137. Ralfs, in Pritch., 
p. 907. Heiberg, De Danske Diat., p. 85. Rab. Fl. Eur. Alg., sect. 
i; p- 182:2 Donkin,..N; H,iBrat.,/Diats, p. 23,. Pl. iv., fig..1.. - This 
form is obviously distinct from that described under the name of Navi- 
cula elegans by Grunow, Verhand. der K. K. Zool. Bot. Gesell., Band 
x., 1860, T.iv., fig. 37. 
Blackrock, Co. Dublin. Caumlough, near Tralee. Lough Gill, 
Co. Kerry. Galway Bay. Breaches, Kilcool, Co. Wicklow. “Tacum- 
shane, Co. Wexford. 
R I. A. PROC., SER. II., VOL. II., SCIENCE. 28 
