O’Mrara—Report on the Irish Diatomacee. 383 
(h) Luscate. 
Valves more or less elliptical ; strie divided into two portions on each 
side of the median line, by two longitudinal suler, forming a tolerably 
broad rhomboidal space about the median line. 
Navicula fusca, (Gregory). Marine. 
Valve oblong elliptical; strize obviously moniliform, radiate ; inter- 
mediate space lanceolate, divided into three compartments, one unstri- 
ate, and having the median line in thecentre, and one on either side 
striate; central nodule large; length about ‘0047, breadth about 
"0022. (Plate 32, fig. 17.) 
RalisyimeuPritehy, pi*8938s) Rabo Fl. Hur. Alg.'» sectyisp: 179. 
Donkin, N. H. Brit. Diat., p. 7, Pl.1., fig.5.—Navicula Smithii var. 
fusca, Gregory, Diat. of Clyde, p. 486, Pl.ix., fig. 15. Schmidt’s 
Atlas der Diat., T. vui., fig. 1. 
Arran Islands; stomachs of Ascidians, Roundstone Bay; stomachs 
of Ascidians, Broadhayen, Co. Galway. Rostrevor, Co. Down. 
Navicula smithit, (De Breb.) Marine. 
Valve broadly elliptical; strize moniliform, slightly radiate ; inter- 
mediate space narrow, lanceolate, consisting of three distinct por- 
tions, one unstriate about the median line, and one on either side of the 
latter striate; length about ‘0027, breadth about :0012. (Plate 32, 
fig k8.) 
Wm. Sm., B. D., Vol. i., p. 92. Smith assents to the suggestion of 
De Breébisson, to change to Navicula smithii the form he had previously 
named Navicula elliptica, B. D., Vol.1., p. 48, Pl. xvi.., fig. 152. For this 
reason Grunow, Heiberg, and Donkin rightly attribute the species to 
De Brébisson. Grunow, Verhand. der K. K. Zool. Bot. Gesell., Band 
x., 1860, p. 531. Heiberg, De Danske Diat., p. 81. Ralfs, in 
Priteh,. p:898i)9 Raby FI. Hur. Alg.,. sect. 1.;. p. 178... Donkin, N. H: 
Brit yDiat..0p.96, Ploi..fer4s oSchmidt’s: Adlas der: Diat.y L.e-viny; 
fig. 16. 
Arran Islands; Stomachs of Ascidians, Roundstone Bay; Sto- 
machs of Ascidians, Broadhaven Bay, Co. Galway. MRostrevor, Dun- 
drum Bay, Co. Down. Bannow, Co. Wexford. Seaweeds, Kilcool, 
Co. Wicklow. 
Var. subrotunda, (O’Meara). Marine. 
Like the typical species, but nearly orbicular. 
Schmidt’s Atlas der Diat., T. vii., fig. 17, fig. 22? 
Stomachs of Ascidians, Roundstone Bay; Arran Islands, Co. Gal- 
way. 
