O’Mrara—Report on the Irish Diatomacee. 289 
Dimeregramma nanum, (Greg.) Marine. 
Frustules on front view slightly arched, short, but broad; end of 
striz appearing at the margin; on side view broadly elliptical, lanceo- 
late; marginal strie long, leaving but a narrow unstriated median 
space. 
Ralfs, in Pritch., p. 790, Plate iv., fig. 33.—Dimeregramma 
Gregorianum, Grunow, Verhand der K. K. Zool. Bot. Gesel., Band 
xli., 1862, p. 346. This last named author changes the specific 
name given by the discoverer, on the ground that the original designa- 
tion answers only for the smaller forms, the species varying greatly as 
regards size. Rabenhorst retains the original specific name imposed 
by Gregory, and adopts the generic name Dimeregramma, but erro- 
neously ascribes the species to Pritchard. Fl. Eur., sect. 1, p. 123.— 
Denticula nana, Gregory, Diat. of the Clyde, p. 23, Pl. x., fig. 34. 
Stomachs of Ascidians, Belfast Lough, Co. Antrim. 
Dimeregramma minus, (Greg.) Marine. 
Frustules on front view as in the preceding species, only narrower 
for the length; on side view narrow, elliptical, and pointed at the 
ends; marginal striz long, leaving the central unstriate band very 
narrow. 
Ralfs, in Pritch., p. 790. Grunow, Verhand der K. K. Zool. Bot., 
Gesel., Band xii., 1862, p. 376, T. iv., fig. 29. Rab. Fl. Eur., sect. 
1, p. 128, who attributes this species as well as the preceding to 
Pritchard.—Denticula minor, Gregory, Diat. of Clyde, p. 23, Pl. x., 
fig. 35. : 
On piles of wooden bridge, Dollymount. On sea-weeds, Ireland’s 
Eye, Co. Dublin. 
Dimeregramma distans, (Greg.) Marine. 
Frustules on front view similar in outline to the preceding species; 
on side view broadly elliptical, and somewhat lanceolate at the ends; 
marginal striz costate,‘short, leaving a broad, unstriate, median space. 
CBG ties 19)) 
Ralfs, in Pritch., p. 790, Pl. iv., fig. 34. Grunow, Verhand der 
K.K. Zool. Bot. Gesel., Band xii., 1862, p. 376. Rab. Fl. Eur., 
sect. 1, p. 123.—Denticula distans, Gregory, Diat. of Clyde, p. 23, Pl. 
x., fig. 36. 
Stomachs of Ascidians, Belfast Lough, Co. Antrim. 
Dimeregramma marinum, (Greg.) Marine. 
Frustules on front view linear, slightly constricted at the ends ; on 
side view linear, with cuneate ends, and slightly expanded in the 
middle; striae moniliform, long, leaving the median unstriate band 
