378 Proceedings of the Royal Ivish Academy, 
tre, where it expands considerably ; expanded area somewhat rounded ; 
strie moniliform, convergent in the middle, then strongly radiate ; 
length -0035; breadth -0017. (Plate 82, fig. 2.) 
Donkin, Q. J. M.8., 1858, p. 17, Pl. m., fig. 19, who attributes 
the species to De Brébisson. Ralfs, in Pritch., p. 908. Cleve, Om 
Svenska och Norska Diat., p. 226. Rab. Fl. Eur. Alg., sect. 1., p. 
201../: Donkin, (Nz. But. Diatyp.' U7, Pisni tee, 
Drehednamaud, near Castlegregory, Co. Kerry. Stomachs of As- 
cidians, Roundstone Bay, Stomachs of Ascidians, Broadhaven Bay, 
Galway Bay, Co. Galway. 
Nawicula humerosa, (De Brébisson.) Marine. 
Valve linear, elliptical, gradually contracted towards the broad, pro- 
duced, rounded ends; shghtly constricted in the middle; striz close, 
moniliform ; puncta small, convergent in the middle, radiate towards 
the ends; intermediate free space narrow, except in the middle, where 
it is broadly and somewhat roundly expanded; length, about -00382, 
breadth, about -00138, and in middle about -9012. (Plate 32, fig. 3.) 
Wm. Smith, (B. D., Vol. u., p. 98), who attributes the species to 
De Brébisson. Ralfs, in Pritch., p. 9038. Rab. Fl. Eur. Alg., sect. i., 
p. 201. 
Bannow, River Slaney, near Killurin. Co. Wexford. Portmar- 
nock, Malahide, Co. Dublin. Seaweeds, Portrush, Co. Antrim. 
Caum Lough, near Tralee, Lough Gill, Co. Kerry. Kilkee, Co. 
Clare. Salt marsh, Kilcool, Co. Wicklow. 
Var. fuscata, (Schumann). Marine. 
Like the typical form, but having the ends slightly capitate, and 
the margins pertectly linear; length :0038, breadth 0014. (Plate 32, 
fig. 4.) 
Likely the same as Navicula fuscata, Schumann, Die Preussische 
Didt.,;peol; hal, figAa. 
Drehidnamaud, near Castlegregory: Lough Gill, Co. Kerry. 
tomachs of Ascidians, Roundstone Bay, Co. Galway. 
Var. quadrata, (Gregory). Marine. 
Like the typical form, but much shorter and relatively broader; 
the margins linear; the ends, too, being broader and less produced ; 
length :0020, breadth -0012.. (Plate 32, fig. 5.) 
Navicula quadrata, Gregory, Q.J.M.S., 1856, p. 41, Pl. v., fig. 5. 
Donkin (N, H. Brit. Diat., p. 18) considers this identical with Navicula 
humerosa, and Ralfs adopts the same opinion in Pritchard, p. 903. 
Lough Gill, Co. Kerry. Stomachs of Ascidians, Broadhaven Bay, 
Co. Galway. Seaweeds, Portrush, Co. Antrim. 
