O’Mrara—Report on the Inish Diatomacee. 405 
Var. intermedia, (O’Meara). Marine. 
Valve considerably smaller than that of the typical form; the 
lobes are more expanded; the ends of the coste on the inner edge of 
the compartments on either side of the median one are longer, the 
ridge seeming to be in this case wider, and not so much elevated. 
This is, perhaps, identical with Navicula crabro, Grunow, Ver- 
hand. der K. K. Zool. Bot. Gesell., Band’ x., 1860, p. 524, T. v., 
fig. 21, and with Navicula nitida, Gregory, Q.J.M.S., 1856, p. 44, 
i, Vey ee 1 
Broadhayen Bay. Roundstone Bay. 
Var. denticulata, (O’Meara). Marine. 
Valve very much smaller than the preceding variety, not so much 
constricted, the ends of the striz appearing on the inner edge of the 
compartments on either side of the median one being of the same 
breadth, or nearly so, as that of the coste of the marginal band of strie, 
which are very narrow. (Plate 33, fig. 34.) 
Navicula denticulata, O’Meara, Q. J. M. S:, 1867, p. 115, Pl. v., 
fig. 2. Inthe description at first given of this form it would appear as 
if the space between the two bands of coste were unstriate ; but upon 
more close examination, with better illumination than I then possessed, 
I have satisfied myself that the coste pervade the interspace. They 
are indeed very indistinct, but still traceable. 
Arran Islands; Stomachs of Ascidians, Broadhaven Bay ; Stomachs 
of Ascidians, Roundstone Bay, Co. Galway. 
Navicula pfitzeriana, N.S. Marine. 
Valve small, slightly constricted; median compartment very nar- 
row, lanceolate; compartments at either side become wider in middle 
than at ends; striate; marginal striate band relatively wide; striw 
linear, close, convergent in the middle, thence finer, and nearly paral- 
lel; length :0017, breadth °0005; breadth at constriction :0004. 
(Plate 33, fig. 35.) 
This form was a considerable time ago Go at by me among 
other interesting species collected by Mr. Mozely, ERENS: Challenger, 
on the coast of Patagonia. It is identical with a specimen from Val- 
paraiso, figured as Navicula divergens by Schmidt, Atlas der Diat., 
T. xu, fig. 53; but as my designation has the priority of publication, 
it has a right to stand. 
Stomachs of Ascidians, coast of Co. Clare. 
Navicula vickersti, N.S. Marine. 
Valve very large, deeply constricted; median compartment linear, 
wide; compartments on either side wide, unstriate, bilunate on the 
outer margin; marginal striate band narrow in the middle, widening 
towards the broadest part of the heart-shaped lobes, and thence decreas- 
ing in width towards the rounded ends; striz costate, nearly parallel 
