O'Meaea — Itejjort on the Irish Diatomacece. 413 



Bot. GeselL, Band x., p. 538, T. v., fig. 16, who found the species in 

 freshwater as well as in brackish. Balfs, in Pritch., p. 905. Schu- 

 mann, Diat. der Hohen Tatra, p. 69. Eab. Fl. Eur. Alg., sect, i., 

 p. 185. It is not improbable that this species is identical with the 

 form described by Gregory as ]S'avicula lepida, var. B. ? Q. J. M. S., 

 1856, p. 7, PI. i., fig. 25, B. 



Bannow, Co. Wexford. Lough Gill, Co. Kerry. In these, fresh 

 water forms and marine were mingled. Glenchree, Killakee, Co. 

 Dublin. Lough Mask, near Tourmakeady, Co. Mayo. The three last- 

 named locaKties were wholly free from mariue influences. Hence I 

 consider that though the form has been found in brackish water, it is 

 essentially a fresh water species. 



Navicula semen, (Ehr.) Eresh water. 



Yalve linear, elKptical, broad ; ends broadly and shortly produced. 

 Striae costate ; convergent in middle, radiate towards ends ; length 

 •0018, breadth -0008. (Plate 34, fig. 22.) 



Kiitz. Bac, p. 99, T. xxviii., fig. 49, who attributes the species 

 to Ehrenberg. Wm. Sm., B. D., Yol. i., p. 50, PL xvi., fig. 141. Hei- 

 berg, De Danske Diat., p. 82. Ealfs, in Pritch., p. 900. Donkin, 

 IT. H. Brit. Diat., p. 21. PI. iii., fig. 8. Schumann, Diat. der Hohen 

 Tatra, p. 68. 



Stream, Bellarena, Co. Derry. Lough Moui'ne deposit, Co. Antrim. 



Navicula humilis, (Donkin), Eresh water. 



Valve small, inflated in the middle, with broad capitate ends. Striae 

 costate, coarse, subdistant, radiate; central nodule large; length "0010, 

 breadth 'OOOS. On front view, frustule quadi'angular, slightly con- 

 stricted in the middle ; costae divergent, leaving a considerable space 

 about the central nodule, which latter appears very highly developed. 



Donkin, U. H. Brit. Diat., p. 67, PI. x., fig. 7. Donkin considers 

 this form identical with ITavicula inflata, var. Gregory, Q. J". M. S., 

 1855, PL ii., fig. 20 c. 



Lough GiU, Co. Keny. Lough Mask, near Tourmakeady, Co. 

 Mayo. 



Navicula inflata, (Kiitz.) Eresh water. 



Yalve small, inflated in the middle ; ends narrowed, produced, 

 and scarcely capitate. Striae closely granular, radiate ; length '0010, 

 breadth -00035. (Plate 34, fig. 23.) 



Kutz. Bac, p. 99, T. iii., fig. 36. Wm. Sm., B. D., Vol. i., p. 50, 

 PI. xvii., fig, 158. Grunow, Verhand, der K, K, Zool. Bot. Gesell., 

 Band x., 1860, p. 538, T. iy., fig. 41. Ealfs, in Pritch., p. 899. Hei- 



