O’Mrara—Report on the Irish Diatomacee. 389 
Navicula francisca, N.S. Marine. 
Valve nearly orbicular; marginal band of strie narrow; median 
band of striz narrow, distant from median line, leaving a lanceolate, 
unstriate space between the inner margins; intermediate space 
between the inner and outer bands of strie broad, unstriate; stric 
moniliform, parallel in the middle, radiate towards the ends; length 
0033, breadth 00380. (Plate 32, fig. 30.) 
Stomachs of Ascidians, Roundstone Bay, Co. Galway. 
Navicula hibernica, N.S. Marine. 
Valve elliptical oblong; marginal band of strie narrow, slightly 
broader in the middle than at the ends; inner band of striz narrow, 
roundly expanded at the ends; intermediate space between the inner 
and outer bands of strie broad, ornamented with irregularly disposed 
distinct puncta; striz of the marginal band linear, with moniliform strize 
interposed, parallel in the middle, radiate towards the ends; strie of 
the inner band punctate, parallel. (Plate 32, fig. 31.) 
Stomachs of Ascidians, Roundstone Bay; Arran Islands, Co. Gal- 
way. 
Navicula nitescens. (Gregory). Marine. 
Valve elliptical, lanceolate ; striae apparently strongly costate, 
divided by a longitudinal sulcus into two nearly equal compartments ; 
free space between the inner margins of the inner bands of strie nar- 
row, lanceolate ; slightly expanded in the middle. (Plate 82, fig. 32.) 
Balianunm, Prtch; p.:89e.- : Rab. Fl. Bur: Ale. sect:1., p. 179. 
Donkin, N. H. Brit. Diat., p. 8, Pl. i. fig. 7.—Navicula smithu, var. 
nitescens, Gregory, Diat. of Clyde, p. 487, Pl. ix., fig. 16.—Pinnularia 
arraniensis, O’Meara, Q. J. M.S8., 1867, p. 116, Pl. v., fig. 6. 
Arran Islands. Stomachs of Ascidians, Roundstone Bay; sto- 
machs of Ascidians, Broadhayen Bay, Co. Galway. 
Navicula richardsoniana, N.S. Marine. 
Valve narrow, elliptical; ends rounded; inner band of strie broad 
outer band of strie very narrow; striz strongly costate, sub-distant, 
radiate; length -0024. breadth -0006. (Plate 82, fig. 33.) 
This form strongly resembles Navicula nitescens, but differs so 
much as to be entitled to be regarded as a distinct species. 
Stomachs of Ascidians, Broadhaven Bay, Co. Galway. 
Navicula stokesiana, N.S. Marine. 
Valve large, rhombic, lanceolate; marginal striate band wide; 
inner striate band narrow, elevated above the surface; free space in- 
