O’Mrara—Report on the Irish Diatomacee. 399 
kinii, Schmidt, Atlas, T. xi., fig. 64. This species is at first view 
extremely like Navicula donkinii; it is, however, considerably larger, 
the strive finer and closer, and valve more deeply constricted. 
Arran Islands; Stomachs of Ascidians, Broadhaven Bay, Co. Gal- 
way. 
Navicula ineurvata, (Gregory). Marine. 
Valve slightly constricted; median compartment tolerably wide, 
slightly inflexed at the ends, very slightly inflexed in the middle; 
compartments at either side about the same width as the median, 
slightly arcuate, unstriate; marginal band of strie narrow; stric 
nearly parallel throughout, fine, tolerably close ; indistinctly punctate ; 
puncta very close; length :0028, breadth -0009; at constriction, 
‘0008. (Plate 33, fig. 24.) 
Gregory, Q.J.M.S8., 1856, p. 44, Pl. v., fig. 13. In this figure 
the marginal band of striz is represented as very much wider than it 
appears to be in any of the very numerous specimens I have met with, 
and also the compartments on either side of the median line are much 
narrower ; in consequence of this, I was induced to consider the form 
distinct from that of Gregory, and named it Navicula pellucida, 
Te Jo sot pollo, Ply. fie..3.. Ralis,.in Pritch., p. 893. 
Donkin, N. H. Brit. Diat., p. 49, Pl. vu., fig. 4. This figure does not 
describe the incurved ends and middle of the median compartment. 
Donkin regards the species as = to Navicula interrupta, Grunow, Ver- 
hand. der K. K. Zool. Bot. Gesell., Band x., 1860, p. 531, T. 111., fig. 20. 
If so, Grunow’s figure is lable to the same remark as that of Gregory. 
—Navicula splendida, var. incurvata, Rab. Fl. Eur. Alg., sect. i., 
p. 204. I think the form obviously distinct from Navicula splen- 
ddida. 
Arran Islands; Stomachs of Ascidians, Broadhaven Bay; Sto- 
machs of Ascidians, Roundstone Bay, Co. Galway. Stomachs of Asci- 
<lians, Co. Clare. 
Navicula musea, (Gregory). Marine. 
Valve small, deeply and suddenly constricted ; ends sharp ; median 
compartment relatively broad, inflexed at ends, slightly constricted in 
the middle; compartments at either side narrow, arcuate, unstriate ; 
marginal band of striee narrow, obscurely punctate, extremely short in 
the middle, radiate towards the ends; length -0012, breadth -0006 ; 
at the constriction, :0004. (Plate 33, fig. 25.) 
Gregory, Diat. of Clyde, p. 479, Pl. ix., fig. 6. This figure by no 
means agrees with the description nor the measurements of the text. 
So that it is not at all to be wondered at that Donkin should have con- 
sidered it identical with that which he has figured as Navicula musca. 
Donkin’s form referred to was properly regarded by Schmidt as a dis- 
