O'Meara — Re2)ort on the Irish Diatomacece. 401 



there, but with precise focusing they disappear, or, if they appear at 

 all, are veiy faint. Schmidt's figure represents the species as more 

 rohiist than mine, but the compartments on either side of the median 

 one are just as in mine. ^ 



Arran Islands ; Stomachs of Ascidians, Broadhaven Bay, Co. Gal- 

 way. 



Navicula lomlus, (Ehr.) Marine. 



Yalves much constricted, lobes much inflated ; median compart- 

 ment very wide, the boundary lines strong, and having the edges 

 milled, greatly curved at the ends, slightly constricted in the middle ; 

 compartments at either side narrow ; scarcely striate, or if striate, the 

 strise very faint ; marginal band of strise very wide ; strife remote, dis- 

 tinctly moniliform, the beads being distant, parallel in the middle, 

 more and more radiate towards the ends ; length '0036, breadth 

 0016 ; breadth at the constriction -0010. (Plate 33, fig. 28.) 



Ealfs, in Pritch., p. 893, who attributes the species to Elirenberg. 

 Gregory, Diat. of Clyde, p. 484, PI. ix., fig. 12. Eab. PL Eur. Alg., 

 sect, i, p. 204. Donkin, N. H. Brit. Diat., p. 50, PI. vii., fig. 7a. 

 This figure fairly represents the characters of the species, but in my 

 specimens the constriction is deeper, and the compartments at either 

 side of the median one are much narrower. Cleve, Om Svenska och 

 Norska Diat., p. 226. 



Arran Islands ; Stomachs of Ascidians, Broadhaven Bay ; Sto- 

 machs of Ascidians, Poundstone Bay, Co. Galway. Ballysodare, Co. 

 Sligo. Malahide, Portmarnock, Co. Dublin. Bannow, Co. Wex- 

 ford. Stomachs of Ascidians, coast of Co. Clare. Stomachs of Ascidians, 

 Belfast Lough, Co. Antrim. 



Navicula entomon, (Ehr.) Marine. 



Yalves not so deeply constricted as in ITavicula bombus ; median 

 compartment narrow, inflexed at the ends, slightly constricted in the 

 middle ; compartments at either side narrow, unstriate, or strise very 

 obscure ; marginal band of strise broad ; striae distinctly moniliform, 

 distant, parallel in the middle, radiate towards the ends ; length 

 •0030, breadth "0012 ; breadth at the constriction -0010. 



This species strongly resembles Navicula bombus in the character 

 of the moniliform strise ; the constriction is, however, not so deep, nor 

 are the lobes so much expanded ; the median compartment also is 

 much narrower in this species than it is in the other. 



Kutz. Bac, p. 100, T. xxviii., fig. 74. In this case, the figure is 

 very obscure. Kiitzing attributes the species to Ehrenberg. Ealfs, in 

 Pritch., p. 893. Donkin, N. H.Brit. Diat., p. 49, PI. vii., fig. 5.' 

 This figure represents the species as much larger, and the compart- 



