O’Mrara—Report on the Irish Diatomacee. 307 
Navicula macula, (Gregory). Marine. 
Valve broadly elliptical, with narrowed truncate ends; length 
°0014, breadth - 0008; cost fine, parallel; intermediate free space 
narrow, except in the middle, where it expands greatly in quadrangu- 
lar form. (Plate 30, fig. 47.) 
Gregory, Q.J.M.S., 1856, p. 43, Pl. v., fig. 9. Ralfs, in Pritch., 
p. 896. Rab. Fl. Eur. Alg., sect. 1., p. 189. 
Lough Guill, Co. Kerry. 
Navicula zellensis, (Grunow). Fresh water. 
Valve narrow; length -0016, breadth -0003; ends produced; 
margin triundulate; strie very fine; intermediate free space narrow, 
except at the middle, where it expands in a short narrow stauroform 
band. (Plate 30, fig. 48.) 
Grunow, Verhand. der K. K. Zool. Bot. Gesell., Band x., 1860, 
p92 E nn, ie..o4 Rab. Fl. Eur.Alg.j sect. 1, ps 207. 
Lough Derryvaragh, Co. Westmeath. Camolin, Co. Wexford. 
(c.) Cuspidate. 
Valves more or less distinctly lanceolate; ends sometimes produced ; 
median line distinet ; intermediate free space narrow, bounded by two 
well-defined longitudinal ridges, one on either side of the median line. 
Navicula cuspidata, (Wm. Smith). Fresh water. 
Valve large, lanceolate; ends cuspidate; length about ‘0070, 
breadth -0015; striz close, fine, linear, parallel; median line with 
slightly elongated expansions near the central nodule. (Plate 31, fig. 1.) 
Kutz. Bac., p. 94, 2. 11... figs. 24 and 27, Wm:,.Sm..B..D. Vol. 
if p44], bs xya., fieatdt,. Rab. Sussw.;Diat.,.p. 37,1. v1., fig: 16. 
This latter author remarks, that this form is very ike Navicula fulva, 
but never attains the same size. This observation is not borne out by 
the specimens I have had the opportunity of examining; Navicula 
cuspidata is usually the larger, sometimes very much so. Ralfs, in 
Pritch., p. 905, Pl. xu., fig. 5. Grunow, Verhand. der K. K. Zool. 
Bot. Gesell., Band x., 1860, p. 528. The form referred to by Grunow 
may possibly be different from the present, as he describes the strize 
as somewhat radiate in the middle; the strie in N. cuspidata being 
parallel all through. Heiberg, De Danske Diat., p. 82. Cleve, Om 
Svenska och Norska Diat., p. 228. Donkin, N.H., Brit. Diat., p. 39, 
Pi vi, 12,6. 
Castlebridge, Tacumshane, Co. Wexford. JDerrylane Lough, 
Stream, Crossdoney, Co. Cavan. Cushendun, Co. Antrim. Pond, 
Botanic Gardens, Belfast, Co. Down. Bellarena, Co. Derry. River 
