O’Mrara—Report on the Irish Diatomacee. 073 
Navicula gohnsonit, (Wm. Sm.) Marine. 
Valve long and narrow ; length, ‘0060; breath, -0005; inflated in 
the middle and at the ends; transverse strize very fine, parallel, longi- 
tudinal striz more easily detected; colour of dry valve whitish. 
CB. 31, tie. 46.) 
Pinnulariajohnsonii, Wm. Sm. B. D., Vol. i., p. 58, Pl. xix., fig. 
179. Rab. Fl. Eur. Alg., sect.i., p. 211. Rabenhorst considers the form 
identical with Navicula seopulorum, De Brébisson. In this opinion he 
agrees with Ralfs, in Pritch., p.895, and Donkin, N. H. Brit. Diat., p. 73, 
Pl]. xii., fig.5. I cannotfindany figure of De Brébisson’s species, Navicula 
scopulorum, and consider the identification of the last named with the 
present species more than doubtful, inasmuch as Kiitzing regards that 
form as identical with Navicula mesotyla, figured by him, Bac., T. v., 
fig. 3, and T. xxviil., fig. 84. These figures are obscure as to details, 
but from the size and outline I would think it impossible to confound 
Navicula johnsonii with them, and therefore I attribute the species to 
Smith, who has described and figured it with unmistakable accuracy. 
This course commends itself the more to my judgment, inasmuch as 
Grunow has described and figured under the name of Navicula scopu- 
lorum a form which is obviously distinct from that under considera- 
tion. 
Bannow, Co. Wexford. Malahide, Portmarnock, Co. Dublin. 
Mouth of the River Nannywater, Laytown, Co. Meath. 
Navicula simulans, (Donkin). Marine. . 
Valve linear, with long cuneate ends; transverse strize very faint; 
longitudinal strize quite noticeable with good illumination, if the valve 
be dry; longitudinal free space narrow, except in the middle, where 
it spreads out to the margin in a narrow stauroform band; length 
‘0030, breadth :0006. (Plate 31, fig. 47.) 
The present species I consider to be identical with that so named 
by Donkin, N. H. Brit. Diat., p. 60, Pl. ix, fig. 3. Donkin considers 
it the same as Amphiprora constricta, Ehr., but in this opinion I can- 
not concur. Donkin does not notice the longitudinal striz ; but in all 
other respects the present form is, in my mind, not distinguishable 
from the species named Navicula simulans by that author. 
Stomachs of Ascidians, Broadhaven Bay, Oo. Galway. Malahide, 
Co. Dublin. 
Navicula delginensis, N.S. Marine. 
Valve rhomboid, gradually attenuated towards the broadly rounded 
ends ; transverse striz very faint; longitudinal strie easily detected, 
more especially at the margin, where there is a strongly marked sul- 
cus ; intermediate free space narrow, lanceolate towards the ends, and 
slightly expanded in the middle; length :0020; breadth in the mid- 
dle 0006. (Pl. 31, fig. 48.) 
This form is in outline very similar to a species described and 
