4 
312 Proceedings of the Royal Irish Academy. 
Rostrevor and Dundrum Bay, Co. Down. Breaches near Newcastle, 
Co. Wicklow. Mouth of the Nannywater, Laytown, Co. Meath. 
Synedra nitzschiodes, (Grun.) Marine. 
Frustules on front view slightly attenuated towards the ends; on 
side view narrow, linear lanceolate. (PI. 28, fig. 39.) 
Grunow does not describe the mode of growth, nor can I say any- 
thing on this subject, as the form has been observed by me only after 
treatment with acid. This species may be distinguished from the last 
by the linear and slightly apiculate form of the side view. 
Grunow, Verhand. der K. K. Zool. Bot. Gesel., Band xii., p. 408, 
T. v., fig. 18. This species was found by Grunow only in the Pacific 
Ocean. 
From stomachs of Ascidians, Roundstone Bay, Co. Galway. From 
seaweeds, Rush, Co. Dublin, where it occurs in tolerable abundance. 
Synedra frauenfeldii, (Grun.) Marine. 
Frustules much larger than the three preceding species on front 
view, but very slightly attenuated at the ends; on front view narrow, 
lanceolate, much attenuated from the middle towards the ends, which 
are slightly dilated; strize fine, marginal in the middle, but as the 
valves become narrow towards the ends, they seem to meet. (PI. 28, 
fig. 40. 
Pies Verhand. der K. K. Zool. Bot. Gesel., Band xii., 1862, p. 
406, T.iv., fig.26. The only habitat given by Grunow is the Red Sea. 
Seaweeds, Dundalk, Co. Louth. The form is more slender than 
that figured by Grunow as above, the apex less dilated, and the strie 
shorter; but in the main features the forms are so like as to leave 
but little doubt of their identity. 
Synedra putealis, N.S. Fresh water. 
Frustules in length 0045, very narrow; on front view slightly 
attenuated towards the ends; on side view narrow, lanceolate, gra- 
dually tapering towards the rostrate ends; striz short; stipes short; 
on which the frustules are crowded in small tablets containing about 
ten in each. (Pl. 28, fig. 41.) 
This form possibly may be identical with that described as Synedra 
tenuis, by Kitzing, Bac., p. 65, T. xiv., fig. 10, but in some respects 
it is so different as to warrant the conclusion that it is specifically 
distinct. Kitzing does not describe the mode of growth nor the 
character of the striz, and moreover alleges that m the species re- 
ferred to, the frustules are exactly linear on front view, whereas in 
the present case they are obviously attenuated. 
St. Fenton’s Well, Sutton, Co. Dublin. Well near the Roman 
Catholic Chapel, Ballinasloe, in both which localities it occurs in 
great abundance, mixed with other forms. 
